Actively stabilized payload support apparatus and methods

ABSTRACT

A payload stabilizer and methods for stabilizing a payload suitable for use with video camera payloads. The stabilizer has a feedback system providing supplemental torques to the payload through a gimbal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/160,675, filed May 20, 2016, which is a continuation-in-partof U.S. patent application Ser. No. 14/267,500, filed May 1, 2014, whichis a continuation-in-part of International Patent Application No.PCT/US2012/063298, filed Nov. 2, 2012, which claims the benefit of U.S.Provisional Patent Application No. 61/587,439, filed Jan. 17, 2012, andU.S. Provisional Patent Application No. 61/554,676, filed Nov. 2, 2011.This application also directly claims the benefit of U.S. ProvisionalPatent Application No. 62/165,461, filed May 22, 2015, and U.S.Provisional Patent Application No. 62/175,666, filed Jun. 15, 2015. Theaforementioned applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to inertial stabilizing devices and tomethods therefore, and is applicable to payloads such as, for example,image capture devices including portable video and film cameras.

Mobile film or video cameras typically require angular and spatialstability in order to obtain smooth, quality results. One type ofstabilizer is a passive inertial camera stabilizer. Passive inertialcamera stabilizers reduce or avoid unwanted angular and spatial motion,while also benefiting from direct operator control. Passive inertialstabilizers are used to support a variety of cameras including, forexample, light-weight hand-held cameras and large cameras. Most passivestabilizers require significant training time and effort to becometechnically proficient in their use. Passive stabilizing systems forlight-weight cameras with reduced moments of inertia, may requiregreater skill and technique for effective use.

Although a variety of camera stabilization systems are available,challenges still remain in providing consistent stabilization control ofpayload platforms. Particularly, there is a need for an activestabilizer system for use with miniaturized/lightweight cameras.

SUMMARY OF THE INVENTION

Embodiments of an actively stabilized payload support apparatus aredisclosed. The payload support apparatus has a gimbal with a firstgimbal axis, for example a roll axis, and a second gimbal axis, such asa tilt axis, wherein the gimbal axes are perpendicular to the secondgimbal axis. The gimbal has a torque generator system that includestorque generators for one or more of the gimbal axes. In an exemplaryembodiment, a rotation measuring device measures an angle θ of rotationof a pan shaft or pan motion, which represents a third gimbal axis.Processing devices are configured to receive angle θ and one or morenon-transitory storage devices on which is stored executable computercode are operatively coupled to the one or more processing devices. Whenthe code is executed algorithms obtain a first gimbal axis torque and asecond gimbal axis torque. The torque generators then generate the firstand second gimbal axis torques.

Further disclosed are payload support apparatuses that can be used withmethods disclosed herein. An illustrative apparatus of the support andstabilizing apparatus has a combination of gears disposed at or near thegimbal to implement the torque corrections. The gears may be acombination of sector gears and drive gears, direct drive configurationsor other suitable components to implement the torque. In an exemplaryembodiment, pan and tilt motors are coupled by a concentric torquegenerator coupler and are contained in a handle of the apparatus.

DESCRIPTION OF THE DRAWINGS

The detailed description refers to drawings briefly described here.Arrows showing rotation in the drawings are merely to indicate rotationand not to limit the rotation as to direction. Components in somefigures are removed to expose other parts of interest. All figures areof illustrative embodiments of an actively stabilizing payload support,components thereof or accessories thereto.

FIG. 1 depicts a stabilizer according to an illustrative embodiment ofthe invention.

FIG. 2 is a block diagram of an illustrative embodiment of the inventionand depicts the correspondence to an illustrative physical structure.

FIG. 3 is a signal processing block diagram of an algorithm applicableto stabilize the tilt axis according to an illustrative embodiment ofthe invention.

FIG. 4 is a signal processing block diagram of an algorithm applicableto stabilize the pan axis according to an illustrative embodiment of theinvention.

FIG. 5 is a signal processing block diagram of an algorithm applicableto stabilize the roll axis according to an illustrative embodiment ofthe invention.

FIG. 6 and FIG. 7 are exploded views of an illustrative embodiment ofthe invention.

FIG. 8 is a flow chart representing the calculation of actual torques tobe generated by the roll and tilt motors.

FIGS. 9A-H show mix factors for roll and tilt with pan axis angles of 0,45°, 90°, 135°, 180°, 225°, 270° and 315° according to an illustrativeembodiment of the invention.

FIG. 10 depicts an apparatus for stabilizing a payload according to anillustrative embodiment of the invention.

FIG. 11 is a transparency view of an apparatus for stabilizing a payloadaccording an illustrative embodiment of the invention.

FIG. 12 is a close up of portions of the pan, tilt and roll mechanismsof the stabilizing apparatus of FIG. 11, according to an illustrativeembodiment of the invention.

FIG. 13 depicts components of a tilt mechanism of the apparatus foractively stabilizing a payload according to an illustrative embodimentof the invention.

FIG. 14 depicts a roll motion limiting mechanism according to anillustrative embodiment of the invention.

FIG. 15 shows components of a tilting mechanism according to anillustrative embodiment of the invention.

FIG. 16 depicts another configuration of an actively stabilized payloadsupport apparatus having a slotted grip, according to an illustrativeembodiment of the invention.

FIG. 17 depicts a portion of an actively stabilized payload supportapparatus with the grip shown transparently, according to anillustrative embodiment of the invention.

FIG. 18 is a cross section of an actively stabilized payload supportapparatus according to an illustrative embodiment of the invention.

FIG. 19 depicts an actively stabilized payload support apparatus with agrip having a scalloped lower edge, according to an illustrativeembodiment of the invention.

FIG. 20 depicts a universal joint within a grip of an activelystabilized payload support apparatus, according to an illustrativeembodiment of the invention.

FIG. 21 shows the scalloped-edged grip of an actively stabilized payloadsupport apparatus, according to an illustrative embodiment of theinvention.

FIG. 22 depicts an actively stabilized payload support apparatus inwhich the roll frame is supported by the grip, according to anillustrative embodiment of the invention.

FIG. 23 depicts a cross section of an actively stabilized payloadsupport apparatus in which the roll frame is supported by the grip,according to an illustrative embodiment of the invention.

FIG. 24 depicts a second cross-sectional view of the actively stabilizedpayload support apparatus of FIG. 23, according to an illustrativeembodiment of the invention.

FIG. 25 depicts an actively stabilized payload support according to afurther illustrative embodiment of the invention, in which the rollframe is supported by the grip.

FIG. 26 is a cross section of an actively stabilized payload supportaccording to the illustrative embodiment of the invention of FIG. 25.

FIG. 27 depicts a boss according to an illustrative embodiment of theinvention.

FIG. 28 depicts a portion of an actively stabilized payload supportapparatus with the grip presented transparently to show a pinion andsector gear mechanism, according to an illustrative embodiment of theinvention.

FIG. 29 depicts a portion of a pinion and sector gear mechanism,according to an illustrative embodiment of the invention.

FIG. 30 depicts a front perspective view of an actively stabilizedpayload support, according to an illustrative embodiment of theinvention.

FIG. 31 depicts a side view of the actively stabilized payload supportof FIG. 30, according to an illustrative embodiment of the invention.

FIG. 32 depicts the actively stabilized payload support of FIG. 30 in afolded position, according to an illustrative embodiment of theinvention.

FIG. 33 illustrates how a tilt sector gear disengages from a tilt pinionwhen an actively stabilized payload support is folded, as configured,according to an illustrative embodiment of the invention.

FIG. 34 depicts a portion of an actively stabilized payload supportshowing an image device holder, according to an illustrative embodimentof the invention.

FIG. 35 is a perspective view of an actively stabilized payload supportapparatus looking down into a stage body according to a furtherillustrative embodiment.

FIG. 36 is a side view of the illustrative embodiment shown in FIG. 35.

FIG. 37 is a back view of the actively stabilized payload supportapparatus shown in FIG. 35.

FIG. 38 is a cross-sectional view through line A-A of FIG. 37.

FIG. 39 is a close up perspective view of a portion of the mechanismshown in FIG. 35.

FIG. 40 is a close-up, cross-sectional view of a portion of FIG. 38.

FIG. 41 is an exploded view of an actively stabilized payload supportapparatus according to an illustrative embodiment.

FIG. 42 is an enlargement of a portion of FIG. 41

FIG. 43 is an enlargement of another portion of FIG. 41.

FIG. 44 is a back view of an actively stabilized payload supportapparatus according to an illustrative embodiment.

FIG. 45 is a cross-sectional view through line A-A of FIG. 44.

FIG. 46 is a close up perspective view of a portion of sector gears ofthe FIG. 45 embodiment.

FIG. 47 depicts an illustrative embodiment of an actively stabilizingpayload support having direct drive motors.

FIG. 48 depicts a further illustrative embodiment of an activelystabilizing payload support having a plurality of gears to generaterotational motion.

FIG. 49 depicts a top view of a stabilizing apparatus according to anillustrative embodiment.

FIG. 50 depicts an iso view of a stabilizing apparatus according to anillustrative embodiment.

FIG. 51 depicts a further iso view of a stabilizing apparatus accordingto an illustrative embodiment.

FIG. 52 depicts a portion of a stabilizing apparatus according to anillustrative embodiment.

FIG. 53 depicts a stabilizing apparatus in a radical tilt positionaccording to an illustrative embodiment.

FIG. 54 depicts a stabilizing apparatus according to an illustrativeembodiment.

FIG. 55 depicts an electronic control unit of a payload stabilizingsystem according to an illustrative embodiment.

FIG. 56 depicts another view of an electronic control unit of a payloadstabilizing system according to an illustrative embodiment.

FIG. 57 depicts a further view of an electronic control unit of apayload stabilizing system according to an illustrative embodiment.

FIG. 58 depicts a schematic of components of a payload stabilizingsystem according to an illustrative embodiment

FIG. 59 depicts a further schematic of components of a payloadstabilizing system according to an illustrative embodiment

DETAILED DESCRIPTION OF THE INVENTION

For simplicity, illustrative embodiments of the actively stabilizedpayload support will be described as they relate to a camera payload.

Illustrative embodiments of the actively stabilized payload supportinclude an arrangement of interdependent sub-assemblies coupled in aninterconnected continuous feedback loop fashion. In an illustrativeembodiment, four possible sub-assemblies include:

1: Balanced Component Assembly

The balanced component assembly includes a “SLED” structure. Anillustrative sled structure is described in U.S. Pat. No. 4,017,168,incorporated herein by reference, where it is designated as “equipmentfor use in hand held photography”. The sled structure will be referredto herein in an abbreviated manner as a rig or stabilizer. Thestabilizer together with a payload, such as a camera and relatedequipment, will be referred to as a “balanced component assembly.”

FIG. 1 depicts a balanced component assembly according to anillustrative embodiment of the invention. Stabilizer 1 comprises aplatform 120 for supporting a camera payload 110 or other payload to beoriented; the platform is coupled to a stiff space-frame 130 extendingaway from and below platform 120. At the distal end of coupledspace-frame 130 are counterweights often consisting of useful componentssuch as a battery 131 and/or a video monitor or simple counter-balanceweights 132. The balanced component assembly has a shifted center ofgravity (CG) outside and below the supported payload's natural center ofgravity where we can place an omni axial gimbal. The omni axial gimbalcomprises a roll axis torque generator 410, a tilt axis torque generator420 and a pan torque generator 430, or other mutually perpendicular setof axes. The omni axial gimbal transfers the weight of the balancedstructure to an external support, such as a handle, which is part of pantorque generator 430, while allowing free rotation of the balancedcomponent assembly about its CG, preferably around any and all possiblerotational axes with respect to the external support's orientation.Attached to the balanced component assembly near its CG is an operatorcontrol or “guide” 140 to which the operator may apply steering torquesto the “sled” to point or otherwise guide the supported payload, such asto frame the subject to be captured by a camera, for example.

As will be shown, illustrative embodiments of the stabilized payloadsupport build upon and may add inertial stability to traditionalbalanced Steadicam®-type or other stabilizing structures, such asstabilizer 1, and work cooperatively with and may use to its advantagenatural passive angular inertia therein. Existing actively stabilizedmounts try to minimize inertia of the camera payload, and thus, mayrequire more accurate and possibly expensive inertial sensors, higherbandwidth and potentially less stable feedback control and more precisephysical structures to achieve the same level of angular stability.Conventional actively stabilized mounts may also be more limited as tothe size and weight of the supported camera.

Illustrative embodiments of the inertial enhancement feature areparticularly applicable to the newer, smaller, lighter, and lowerinertia rigs such as the Steadicam Merlin® sold by The Tiffen Company,LLC. As will be shown, illustrative embodiments of the activelystabilized payload support multiply angular inertia, which may makethese small rigs less susceptible to wind disturbance and inadvertentoperator input, possibly making them perform like larger/heavier rigswithout adding significant weight/size.

Referring again to FIG. 1, attached to and responsive to stabilizer 1 isthe next component, namely:

2: Angular Motion Sensing Unit.

Angular motion sensing units, such as inertial measurement units (IMUs),for example, typically measure the angular rotation rates and linearaccelerations and the orientation with respect to gravity of the objectsor vehicles to which they are attached. In an illustrative embodiment, aso called “six degrees of freedom” angular motion sensing unit isemployed measuring the composite angular rotation rate of the attachedstabilizer plus camera about three substantially mutually orthogonalaxes by so called “angular rate sensors” and the spatial accelerationalong three linear and mutually orthogonal axes via accelerometers. Thethree angular rate sensors are typically mounted in alignment with thecamera's, or other payload's, “roll”, “tilt” and “pan” axes of rotation.The linear accelerometers of the angular motion sensing unit aretypically aligned along the camera's “up-down”, “left-right” and“fore-aft” axes. The accelerometers respond to actual linearacceleration through space as well as the static acceleration due togravity, the latter useable to detect the steady state angles oforientation of the camera payload referenced to earth based“vertical/horizontal” directions.

According to illustrative embodiments of the invention, the angularmotion sensing unit preferably estimates all possible motions of thesled plus payload and allows development of stabilizing counter-torquesvia the feedback controller algorithms, which will be described below.

The phrase “supplemental torques” is used to mean “stabilizing countertorques”, “counter torques”, “supplemental torques”, “correctionaltorques”, or “stabilizing torque signals”, which are torques appliedactively through the gimbal's attached omni-axial torque generator 4 toachieve stability.

By estimating the balanced component assembly's rotation via the angularrate sensors and its gravitational orientation via the accelerometers,the algorithms have information signals required to develop stabilizingcounter torques creating the stabilizing adjustments developed by thenext sub-assembly, of FIG. 1 which is responsive to the angular motionsensing unit, namely:

3: The Signal Processor and its Supported Feedback Controller, and theCombination of Both Algorithmic Methods that it Supports:

Feedback Controller 3 receives motion signals from the angular motionsensing unit subassembly 2 and through a combination of algorithmsproduces stabilizing counter torque signals. These counter torquesignals are converted to physical torques with the omni-axial torquegenerator 4, comprising for example three individual torque generators410, 420, 430 responsive to the stabilizing counter torque signals.Torque generators 410, 420, 430 produce torques about the roll axis,tilt axis, and pan axis, respectively. The angular motion sensing unit 2measures the resulting rotational orientation and rates and producesrepresentative signals that are fed back to feedback controller 3 tocomplete a feedback loop producing the desired stability.

Feedback Controller 3 with its algorithms, which is responsive toangular motion sensing unit subassembly 2 shown in FIG. 1 and co-locatedwith payload 110, monitors the maximum supplemental torques available tobe generated and coupled between the payload (camera) side of the gimbaland the operator side. Feedback controller 3 further synthesizes aninertial enhancement, static and dynamic frictional and leveling torquesand combines them so that the operator experiences them at control guide140 of the stabilizer in a preferably substantially natural way suchthat the operator may be unaware that the unit is actively stabilized.In an exemplary embodiment of the actively stabilized payload support,the device mimics the feel of a passive stabilizer via the stabilityenhancement features and acting additively to the physical rig's naturalpassive feel.

In an exemplary embodiment of the actively stabilized payload support,the operator is provided with a familiar “hands on” way to orient thebalanced component assembly while Feedback Controller 3 actssimultaneously and cooperatively to enhance or otherwise modifystability.

Feedback Controller 3 hardware supporting the algorithms is implementedby a so called “real time signal processor”, such as a digital signalprocessor. “Real time” as used herein means that the processor willreceive input signal(s), act upon them pursuant to the algorithms andproduce a final result with a delay short enough that it will notnegatively affect the stability or performance of Feedback Controller 3and its controlled structure.

In an illustrative embodiment of the actively stabilized payloadsupport, processed in the first part of Feedback Controller 3 algorithmcombination are angular motion sensing unit 2 sensor signals using, orbased upon, algorithms such as those known as “vertical gyro”,“artificial horizon” or “attitude and heading reference system (AHRS)”algorithms, referred to herein as an “artificial horizon” algorithm 310of FIG. 2. This algorithm receives the “vehicle referenced” (in thisillustrative case, camera payload referenced) signals, such as 210 a, b,c, d, e, f from inertial sensors attached to camera payload 110 andconverts them to “earth-referenced” signals, such as 350 a, b, c, d, e,f that are useable (preferably directly) by subsequent algorithms 320,330, 340, for example. “Earth-referenced” as used herein means thatartificial horizon algorithm 310 produces motion signals that representthe roll/pitch/yaw rates of rotation and absolute angular orientation ofcamera payload 110 with respect to the earth and in particular withrespect to a plane that is parallel to the earth's local horizon, andthus, is perpendicular to the direction of local gravity. As applied toorienting a camera, as opposed to an air or space vehicle, theequivalent terms “roll/tilt/pan” are used instead of “roll/pitch/yaw”rates and absolute angles.

Artificial horizon algorithm 310 estimates absolute earth-based tilt androll angles of the supported payload despite lateral accelerationmotions. This can be likened to creating a virtual “stable table,” uponwhich the camera platform can be virtually mounted, facilitatingstability enhancements, such as those described next.

Note that the terms “inertia”, “angular inertia”, and “moment ofinertia” are used interchangeably throughout this description as theyrelate to angular stabilization.

Stability enhancement algorithms implementation will now be explained.According to illustrative embodiments of the actively stabilized payloadsupport, referring now to FIG. 2, we subdivide and implement theremaining algorithmic methods in three parallel paths, each assigned toa particular axis of rotation of stabilizer 1 and each producing acorrective torque applied through a corresponding axis of omni-axialtorque generator 4 attached to a gimbal of the stabilizer 1, namely:

-   -   (1) Roll Axis Algorithm 320 implements the horizon leveling        feature by applying supplemental torque through the roll axis of        the gimbal mounted torque generator 410.    -   (2) Pan Axis Model Follower Algorithm 340 implements the pan        inertia enhancement plus static and dynamic frictions for this        axis by applying supplemental torque through the pan axis of the        gimbal mounted torque generator 430.    -   (3) Tilt Axis Model Follower Algorithm 330 implements the tilt        inertia enhancement plus static and dynamic frictions for this        axis by applying supplemental torque through the tilt axis of        the gimbal mounted torque generator 420.

It is noted that “roll”, “pan” and “tilt” are used for illustrativepurposes, but as mentioned earlier, they can be replaced by othermutually perpendicular axes.

The algorithmic separation between roll, tilt and pan axis algorithms320, 330 340, allows stability corrections of different strengths to beapplied to each axis, which may be advantageous because conventionalbalanced stabilizing rigs may exhibit differing amounts of naturalangular inertia about each primary axis of rotation. For example, thetilt and roll axis inertia is usually greater than the pan inertia dueto the typical sled being somewhat taller than it is deep or wide.Illustrative embodiments of the actively stabilized payload support maycreate a stabilized rig that may equalize the angular inertia among allaxes as perceived by the operator at the control handle/guide ifdesired.

Description of the Stabilizing Algorithms for Each Axis:

Roll Axis Algorithm 320 of FIG. 2 and FIG. 5—Horizon leveling:

Roll Axis Algorithm 320 according to an illustrative example provides,optionally with no additional moving parts to the assembly 1, a horizonleveling feature. Operators of traditional stabilizers dedicatesignificant mental effort in keeping it level. Having this low levelchore done automatically frees the operator to concentrate on theframing of the camera move at hand and navigating through the set toachieve the shot. Furthermore, since the leveling feature is providedthrough active gimbal torques, the balanced component assemblycomprising stabilizer 1 may be neutrally balanced instead ofbottom-heavy as is the custom. Advantageously, in an exemplaryembodiment of the invention, an operator may tilt at will withoutfighting the constant torque of a bottom-heavy rig resulting in morestable framing at larger tilt angles. Importantly, roll axis algorithm320 causes the horizon leveling to be maintained a plurality of or alltilt angles and while panning at all or many practical speeds.

Illustrative embodiments of the invention may mimic the inherently levelhorizon of a ground-based and leveled tripod or dolly plus cameraattached to a standard pan-tilt mount. Such an arrangement allows anoperator to frame and follow a subject by pushing on a so calledpan-tilt handle, freely “panning and tilting” to capture the subject allwhile the camera's horizon remains automatically level, thus, of noconcern to the operator. By construction and set-up, the tilt axis of aground-based mount is typically parallel to the ground so the mountedcamera typically remains level.

Referring to FIG. 5, the aforementioned horizon leveling is achievedusing two signals provided by the artificial horizon algorithm 310: rollaxis measured rate 350 e and absolute roll axis measured angle 350 freferenced to earth. The roll angle is arranged to read zero when thecamera is level (tilt axis is horizontal) and to read positive when thecamera is non-level clockwise, negative when non-level counterclockwise.Similarly, the roll rate is zero when the camera is not rotating aboutthe roll axis, positive if in motion rotating clockwise, negative if inmotion rotating counterclockwise about the roll axis. We scale each ofthese signals by selected scale factors C1, C2 respectively (321, 322)and sum them with adder 326 to create a ‘roll counter torque’ feedbacksignal 325, i.e. supplemental roll torque, applied throughgimbal-mounted roll torque generator 410. With properly selected scalefactors a rapidly responsive feedback loop is created that coaxes therig plus camera back to level despite external disturbances.

Pan and Tilt Axis Algorithms—Enhanced Inertia Plus Static and DynamicFrictions, Referring to FIG. 2:

In addition to inertial enhancement, pan and tilt axis algorithms 340,330 add to a stabilizer assembly's features from the standardground-based camera's fluid damped pan-tilt head, namely dynamic andstatic friction, referenced to a fixed inertial frame provided byartificial horizon algorithm 310. Static friction helps the cameraoperator maintain a fixed pan/tilt orientation—so called “lock-off” withreduced or minimal effort. Dynamic friction typically enhances slow panand tilt smoothness particularly with long (telephoto) lenses. Both ofthese synthesized frictions may also help attenuate camera disturbancesdue to wind gusts and excessive operator input to the guide 140.

Pan axis algorithm 340 and tilt axis algorithm may be identical but mayemploy different inertia, static friction, and dynamic frictionobjectives, creating a separately controllable desired response for eachaxis.

Tilt axis model follower algorithm 330 is responsive to artificialhorizon algorithm 310 provided angular tilt rate 350 a and absolute tiltangle 350 b produce a supplemental tilt torque 335 applied through theomni-axial torque generator's tilt axis via tilt torque generator 420.

Similarly, pan axis model follower algorithm 340 is responsive toartificial horizon algorithm 310 provided angular pan rate 350 c and panangle 350 d produce a supplemental pan axis corrective torque 345applied through the omni-axial torque generator's pan axis via pantorque generator 430.

Note that pan angle is relative to an arbitrary starting position and isnot absolute as with roll/tilt since the artificial horizon algorithmgives no absolute indication as to which direction the camera ispointing pan-wise without a compass or the like. The pan axis algorithmaccounts for this by computing corrective torques based on changes inpan angle not absolute pan angular direction.

The Pan/Tilt axis algorithm will now be described referring now to FIG.3 and FIG. 4. Synthesized inertial enhancement plus beneficial frictionsare added to the pan and tilt axes of a passive balanced componentassembly. Algorithms for the pan and tilt axis simulated physical models341, 331 are employed plus pan and tilt axis model followers 346, 336are employed. The basic technique comprises building a real timesimulation of an idealized model that mimics the physics of the desiredenhanced balanced component assembly within the signal processor. Thesimulated balanced component assembly is driven by an estimate of netexternal pan/tilt torques signals 343, 333 applied to the actual passivebalanced component assembly. The simulated balanced component assembly'scomputed desired motions are then compared to the actual passivebalanced component assembly's measured motions and correctional feedbacktorques based on differences thereof are developed that coerce thephysical balanced component assembly's motions in an effort to matchthose of the simulated one. If omni-axial torque generator 4 is powerfulenough and the bandwidth of the feedback loop is high enough, thebalanced component assembly will generally closely match (and possiblyfeel nearly identical for the operator) to the idealized simulatedmodel.

A physical mechanism that models the desired inertia feature is aflywheel mounted on a relatively low friction bearing. The simulatedflywheel obeys Newton's laws of rotational motion: If stationary (notrotating) it remains so unless acted upon by an applied external torque.If rotating, it continues at a constant angular rate (in degrees persecond for example), either clockwise (CW) or counterclockwise (CCW)unless acted upon by an applied external torque. The flywheel has onlytwo states of being versus time, also known as “states”: its currentrotational rate (a positive CW value, or a negative CCW value, or zeroin degrees per second) and current angular position in degrees. If aconstant torque is applied to the stationary flywheel it begins torotate from zero at an ever increasing angular rate, i.e. it angularlyaccelerates in proportion to the applied torque divided by theflywheel's modeled moment of inertia. Equivalently, its angular rateincreases uniformly over time from zero. If a negative torque is appliedto the flywheel it decreases its angular rate uniformly for the timethat the torque is applied, eventually stopping then reversing directionif the negative torque persists long enough.

Newton also relates angular position to angular velocity: for example ifthe flywheel is rotating at a constant rate of one degree per second itsangular position advances one full turn in 360 seconds or two full turnsin 720 seconds, etc.

The behavior of the modeled inertial flywheel, (i.e. torque input overtime produces angular rate over time and angular position over timeoutputs) can be encapsulated in the following equation set:Angular rate over time=(integral of [torque in] over time) divided bymoment of inertia.

Angular position over time=integral of angular rate over time. Note thatthe “integral over time” of a time variable quantity is simply the “areaunder the curve” accumulated below that quantity plotted on a graphversus time, starting at time zero and ending at the current time. Thesignal processor uses the accepted integrator or accumulator for thisfunction.

Referring to FIG. 3, we describe the above equation implementation forthe tilt axis simulated physical model 331: Torque signal 331 r isdivided by desired moment of inertia Imt by divider 331 s producingmodeled tilt angular acceleration 331 m. Integrator 331 d integratesover time the modeled tilt angular acceleration 331 m producing modeledtilt rate signal 331 h, passed to second integrator 331 g, whichintegrates it over time to produce modeled tilt angle 331 j. Based onthe state of 331 n (0 or 1) a selector switch 331 e passes to 331 peither the signal 331 h when torque is not saturated as detected by 331f, or signal 350 a when torque is saturated as detected by 331 f.

Similarly, for the pan axis, referring now to FIG. 4: Torque signal 341r is divided by desired moment of inertia Imp by divider 341 s producingmodeled pan angular acceleration 341 m. Integrator 341 d integrates overtime the modeled pan angular acceleration 341 m producing modeled panrate 341 h, passed to second integrator 341 g, which integrates it overtime to produce modeled pan angle 341 j. Based on the state of 341 n (0or 1) a selector switch 341 e passes to 341 p either the signal 341 hwhen torque is not saturated as detected by 341 f, or signal 350 a whentorque is saturated as detected by 341 f.

The desired simulated static and dynamic frictional torques are nowadded to the simple inertia only flywheel model. This is equivalent toadding a ‘brake’ to the flywheel. The brake applies a new opposingtorque to the model. If the current angular velocity of the model iszero, we apply a ‘static friction’ holding torque that matches andpreferably completely opposes (is subtracted from) all external torquesinput to the model up to a set threshold. When external torque appliedto the model approaches the set threshold we gradually ‘release thebrake’ (gradually remove the holding torque) allowing the model to beginangularly accelerating in response to the full external torque. When theangular velocity approaches zero the model gradually reapplies the‘static friction’ brake. This results in a braking torque coupled fromthe camera side through the gimbal to the support side via theomni-axial torque generator 4 and its controlling algorithms as will bedescribed.

Referring to FIG. 3 for the tilt axis; a static braking model 331 aresponds to net external tilt torque signal 333 and as described eitherpasses it directly as tilt torque signal 331 k, when modeled tilt ratesignal 331 h is nonzero, or passes torque of zero to tilt torque signal331 k when tilt torque signal 333 is less than a selected thresholdwhile modeled tilt rate signal 331 h is nominally zero.

Referring to FIG. 4 for the pan axis; a second static braking model 341a responds to net external pan torque signal 343 and as described eitherpasses it directly as pan torque signal 341 k, when pan modeled ratesignal 341 h is nonzero, or passes torque of zero to pan torque signal341 k when net external pan torque signal 343 is less than a secondselected threshold while modeled pan rate signal 341 h is nominallyzero.

In parallel to the static friction brake we employ a simulated dynamicfriction braking component. This is achieved by adding a dynamicnegative feedback torque to the input of the model in opposition to theexternal torque input. The dynamic negative torque is achieved simply bycreating and applying a new torque in scaled proportion to the currentangular rate of the model and subtracting the new torque from theexternal torque input with the difference applied to the model. A scalefactor, also known as the ‘coefficient of dynamic braking’ controls thestrength of the dynamic braking effect and when increased is comparableto tightening the ‘drag adjusting knob’ of a conventional passive fluiddamped pan-tilt camera mount.

As a result, the dynamically braked flywheel model responds differentlyto torque input than does the inertia only version. The inertia onlyversion accelerates continuously with ever increasing angular rate givena constant torque input. With the dynamic braking applied the modelangularly accelerates until dynamic braking negative torque equalsexternal torque resulting in preferably net zero torque to the model,which thus settles into constant angular rate motion. This typicallywill closely model the desirable performance characteristic of the fluiddamped pan tilt mount.

For the tilt axis, dynamic braking model 331 b responds to the currentmodeled tilt rate signal 331 h, scaling it by a ‘tilt axis coefficientof dynamic braking’ and produces a tilt dynamic braking torque 331 n,which is subtracted from static braking model 331 a modified tilt torquesignal 331 k using subtractor 331 c.

For the pan axis, dynamic braking model 341 b responds to the currentmodeled pan rate signal 341 h, scaling it by a ‘pan axis coefficient ofdynamic braking’ and produces a dynamic braking torque 341 n, which issubtracted from static braking model 341 a modified pan torque signal341 k using subtractor 341 c.

According to an illustrative embodiment, a modification to the describeddynamic braking feature comprises adjusting the ‘coefficient of dynamicbraking’ as a function of rig rotational rate. For instance, we wouldnormally apply maximum dynamic braking for low rotational rates, whichtypically occur for slow pan and tilt moves called for when using a long(telephoto-type) lens. On the other hand, the natural “friction free”behavior of a traditional passive rig allows very fluid rotating pan andtilt moves launched by the operator by applying some torque to the rigand simply letting go to let it ‘coast’ to follow a subject. If wegradually reduce the dynamic braking coefficient to zero above a certainaxial rotation rate we can accommodate this type of operator movewithout losing beneficial friction enhanced low pan/tilt rate stability.Thus, the ‘coefficient of dynamic braking’ implemented by dynamicbraking models 331 b, 341 b of the tilt and pan axis algorithms,respectively, may be a non-linear function of the respective modeledrates 331 h, 341 h rather than a simple proportional scaling constant.

Further, according to the illustrative embodiment, and as statedearlier, for the tilt and pan axis simulated physical models 331, 341 torespond similarly to actual passive structures, they respond (be drivenby torques) as is the stabilizer assembly 1. That is, the models only orprimarily respond to torques applied by the operator to the controlguide 140 and/or by external disturbances such as wind/air resistanceand imbalance torque. The model preferably does not respond to thetorques applied through the omni-axial torque generator 4 to which thephysical rig 1 is also responsive. In other words, the model preferablyis not driven with the total torque derived from the motion signalsprovided by the artificial horizon algorithm, as it is responsive to alltorques the physical rig feels (since the angular motion sensing unit isfixed to the rig), including the supplemental torque, absent aconfiguration to create a different outcome, thus, it is termed “TotalTorque”. A “Net External Torque” representing the operator input andexternal disturbances should be the only driver of the model.

According to this illustrative embodiment, the axis algorithm, such asalgorithms 320, 330 or 340, has enough information to estimate thisquantity. We first estimate Total Torque by differentiating the axis(pan or tilt) angular rate from the artificial horizon algorithm (thatis estimate the slope of the rate signal versus time). Thisdifferentiator output is a measure of angular acceleration about theaxis. Again using one of Newton's laws we produce:“Total Torque”=“Structural Moment of Inertia” times “angularacceleration”

Where the “Structural Moment of Inertia” is a known physical constantvalue that may need only be measured once for the particular physicalrig axis we are controlling.

We also know the “supplemental torque” generated through the omni axialtorque generator about the axis, since it is generated and applied asthe final result of this axis algorithm, thus:“Net External Torque”=“Total Torque” minus “supplemental torque” foreach axis.

This is the value applied to the simulated physical model. Thiscompletes a model with the desired inertial and frictionalcharacteristics, which model can provide angular rate and position goalsfor use in the next algorithm.

Specifically for the tilt axis, referring to FIG. 3, the ‘total tilttorque’ 337 is estimated using total tilt torque estimator 334, whichdifferentiates the tilt axis measured rate 350 a with signaldifferentiator 334 a—then scales the differentiator output by a constantrepresentative of the known structural inertia about the tilt axis 334 cusing multiplier 334 b to form ‘total tilt torque’ 337.

Finally we subtract known ‘supplemental tilt torque’ 335 from ‘totaltilt torque’ 337 using subtractor 332 to produce ‘net external tilttorque’ 333 applied to the tilt axis simulated physical model 331.

For the pan axis, referring to FIG. 4, the ‘total pan torque’ 347 isestimated using total pan torque estimator 344, which differentiates themeasured pan rate 348 a with signal differentiator 344 a, then scalesthe differentiator output by a constant representative of the knownstructural inertia about the pan axis 344 c using multiplier 344 b toform ‘total pan torque’ 347.

Finally known ‘supplemental pan torque’ 345 is subtracted from ‘totalpan torque’ 347 using subtractor 342 to produce ‘net external pantorque’ signal 343 applied to the pan axis simulated physical model 341.

The remaining sub-algorithm of this illustrative embodiment for the panand tilt axis, the Model Follower will now be described:

In the model follower algorithm the simulated axis physical models 331,341 become the ‘master reference’ and provide modeled angular rate andposition goals as already described. The entire balanced componentassembly becomes the ‘slave’ which will be nudged or coerced—via thesupplemental tilt and pan torques 335, 345 from the torque generator4—to match the rate and position goals dictated by the simulatedphysical model master. If the difference between slave and master iskept small enough the total balanced component assembly may respond andfeel to the user closely to a real rig with the stability enhancedphysical characteristics that the model simulates.

The artificial horizon algorithm 310 provides the measured rate andorientation of each controlled axis of the rig. From here a feedbackloop can be formed to produce the final supplemental torque for eachaxis. Measured rate and orientation of the physical slave is compared tothe modeled rate and position goals of the master by subtraction. Thesedifferences are scaled and summed to form the final supplemental torquefor this axis. More specifically, the following equation can be used:“Supplemental Torque”=K1 times (modeled_rate minus measured_rate) plusK2 times (modeled_angle minus measured_angle)

This equation forms a negative feedback loop wherein the bandwidth anddamping of the loop is controlled by choice of the feedback coefficientsK1, K2. K1 and K2 are preferably set as large as possible to maximizethe fidelity of the slave to the master model. However, typically,practical inertial sensors have some residual electrical noise that willintroduce jitter into the system if these coefficients are set toolarge; therefore the optimum will vary for various examples of theinvention.

The polarity of the “supplemental torque” is chosen such that if thephysical slave ‘falls behind’ the master model a positive “supplementaltorque” is produced that advances the slave through torque from thetorque generator causing it to catch up with the master, conversely ifthe slave moves ahead of the model a negative torque at the generatorretards the slave so it ‘falls back’ to the master model's positiongoal.

Specifically for the tilt axis, in reference to FIG. 3, the modelfollower 336 is implemented by first subtracting tilt axis measured rate350 a from modeled tilt rate signal 331 h forming difference 336 f usingsubtractor 336 a. Secondly, tilt axis measured angle 350 b is subtractedfrom modeled tilt angle 331 j forming difference 336 g using subtractor336 d. Finally, differences 336 f, 336 g are scaled by constants Kt1,Kt2, respectively using constant multipliers 336 b and 336 e,respectively and summed via adder 336 c to form final supplemental tilttorque 335.

For the pan axis, in reference to FIG. 4, the model follower 346 isimplemented by first subtracting pan axis measured rate 348 a frommodeled pan rate signal 341 h forming difference 346 f using subtractor346 a. Secondly, pan axis measured angle 348 b is subtracted frommodeled pan angle 341 j forming difference 346 g using subtractor 346 d.Finally, differences 346 f, 346 g are scaled by constants Kp1, Kp2,respectively using constant multipliers 346 b and 346 e, respectivelyand summed via adder 346 c to form final supplemental pan torque 345.

This completes the basic axis algorithm applied individually to the panand tilt axes for this illustrative embodiment.

Additional Aspects of the Pan and Tilt Axis Algorithms

The practical shortcomings of the described standard “physicalsimulation model plus model follower” algorithms may be addressed byvarious illustrative embodiments of the invention. The aforementionedalgorithms are effective for as long as the generated supplementaltorques remain large enough to overcome the strength of the operator'sapplied torque and will thus keep the physical rig substantially alignedwith the model.

For any practical realizations of the invention, the omni-axial torquegenerator 4 may be of limited maximum torque due to size and weightlimitations of the practical torque motors employed.

Assume for example the standard conventional algorithm is simplyemployed as described previously. If the operator applies an everincreasing torque, the ‘slave’ (physical structure) will faithfullyfollow the ‘master’ model and the apparatus will accurately provide thedesired stability features of inertia enhancement and friction until theomni-axial torque generator 4 reaches its maximum available torque. Atthat point the ‘feel’ of the balanced component assembly suddenlychanges because there is not enough additional supplemental torqueavailable to coerce the rig to match the model. The balanced componentassembly will instantly lose synthesized inertia and will begin to speedup unexpectedly as the operator continues to apply more torque. Asorientation of the physical structure races ahead, it begins tosignificantly outpace the model's positional goal. The operator finallysenses the change in feel and instinctively begins to reduce or releasecompletely his/her torque applied to the rig. The torque generatorfeedback loop eventually comes out of saturation and senses that thebalanced component assembly is angularly way ahead of the model'sposition goal so it applies a maximum torque in the opposite directioncoercing the physical rig to rapidly ‘fall back’ to match the model.This produces, what some may find as an annoying and clearlyunacceptable ‘servo-instability’ or ‘reverse spring back’ physicalbehavior as the algorithm strives to reestablish a positional matchbetween physical rig and model.

Illustrative embodiments of the invention address the aboveshortcomings. Rather than employing the standard physical model with afixed modeled moment of inertia and fixed coefficient of dynamic brakingfriction, instead the system automatically reduces the above two modelparameters over time in response, for instance, to a function ofincreasing measured angular rate about each controlled axis.

Thus, as the operator applies constant torque about a selected axis, themeasured angular rate about that axis gradually increases and themodeled moment of inertia and dynamic braking strength are graduallyreduced. This causes the physical rig to begin to accelerate morequickly than expected but gradually enough so as to produce a timely cuesensed by the operator allowing him/her to reduce applied torque beforethe torque generator reaches maximum and possibly deleterious resultsoccurs.

Should the operator ignore the above cueing feedback feature, the notedunacceptable ‘spring-back’ effect can be further mitigated by firstsensing when an axis torque generator reaches its maximum torquesaturation point. When this occurs the simulated physical model'sangular position goal is overridden and replaced with one that lags thephysical angular position by a constant amount equal to the model tophysical difference that existed when saturation occurs. Thismodification can ensure that the modeled to physical angular positiondisparity remains small enough that little or ‘no spring-back’ occurswhen the operator finally releases control of the handle.

Preferably the result of these novel modifications to the simulatedphysical model is that the stabilized structure of illustrativeembodiments of the invention respond to the operator's inputs in arepeatable and controllable way such that although it may notnecessarily respond ideally—with fixed enhanced inertia plus friction—itstill may be entirely productive in the hands of even an inexperiencedoperator.

Specifically for the tilt axis, in reference to FIG. 3; The tilt axismodifications are implemented by first reducing the ‘tilt axiscoefficient of dynamic braking’ within the dynamic braking model 331 bin response to modeled tilt angular rate signal 331 h increases.Further, the modeled moment of inertia Imt within divider 331 s isreduced as modeled tilt rate signal 331 h increases. This provides thedescribed desired operator cue. Secondly a ‘torque saturation detector’331 f indicates when the tilt axis torque generator 420 reaches itsmaximum value, and in response toggles switch 331 e to its downwardposition, replacing modeled tilt rate signal 331 h with tilt axismeasured rate 350 a to the integrator 331 g input via switch 331 eoutput 331 p connected to the integrator input. This has the desiredeffect of causing modeled tilt angle 331 j to lag or lead tilt axismeasured angle 350 b by no more than the difference that existed whensaturation occurred, as needed to prevent spring-back instabilitiesabout the tilt axis.

Similarly for the pan axis, in reference to FIG. 4; The pan axismodifications are implemented by first reducing the ‘pan axiscoefficient of dynamic braking’ within the dynamic braking model 341 bin response to modeled pan angular rate signal 341 h increases. Further,the modeled moment of inertia Imp within divider 341 s is reduced asmodeled pan rate signal 341 h increases. This provides the describeddesired operator cue. Secondly another ‘torque saturation detector’ 341f indicates when the pan torque generator 430 reaches its maximum value,and in response toggles switch 341 e to its downward position, replacingmodeled pan rate signal 341 h with pan axis measured rate 348 a to theintegrator 341 g input via switch 341 e output 341 p connected to theintegrator input. This has the desired effect of causing modeled panangle 341 j to lag or lead pan axis measured angle 348 b by no more thanthe difference that existed when saturation occurred, as needed toprevent spring-back instabilities about the pan axis.

Although the independent stabilizing algorithms have each been describedas assigned to a separate physical axis of rotation of the rig, thescope of illustrative embodiments of the invention include analternative that simultaneously models the physical motion of a threedimensional structure in all of its possible rotations, notwithstandingpotentially different angular inertias among its axes. A combinedalgorithm creates the stability enhancements via a three dimensionalcorrective torque vector applied through the omni-axial torque generatorattached to the rig's gimbal. The torque vector aligns with the axis (inthree dimensions) about which the torque is to be coupled and has lengthrepresenting the quantity (clockwise or counterclockwise) of generatortorque to be coupled between the ‘operator’ side and the ‘payload’ sideof the gimbal.

Another observed and generally undesired behavior of the described roll,tilt, pan algorithms is noted and addressed in illustrative embodimentsof the invention by further modifications: Specifically, as the physicalstructure is tilted to a high angle of tilt approaching 90 degrees,known as a the ‘zenith’ angle the previously described roll horizonleveling algorithm approaches a singularity where its mimicry of thestandard pan-tilt mount breaks down and becomes unproductive.

If you observe the behavior of a passive conventional ground basedpan-tilt head that can reach 90 degrees of tilt an interestingphenomenon occurs as it approaches the tilt ‘zenith’: Pushing on thepan-tilt handle in the ‘pan’ direction increasingly ‘rolls’ the cameraabout its roll axis and at true zenith the mechanism locks andcamera-referenced pan is no longer possible. While at zenith you arestill able to tilt away from zenith and roll about the camera's rollaxis but can no longer pan about the camera's pan axis. This behavior,commonly referred to as ‘gimbal lock’ is avoided in conventional pantilt mounts as they are constrained to somewhat less than +/−90 degreetilt range.

As exemplary embodiments of the invention are freely hand carried thereis little or no physical way to avoid operator tilts through zenith,furthermore the traditional body carried Steadicam®-type mount allowscontrollable tilt orientation through zenith as the operator canposition the gimbal to avoid gimbal lock since the gimbals' axes are notconstrained to align with those of the camera.

Therefore, alternate algorithmic rules are justified and can bebeneficial to illustrative embodiments of the invention.

Roll Axis Modification for Extreme Tilt Angles:

For a range of tilt angles, say within +/−80 degrees or so of horizontalthe described roll axis leveling algorithm prevails. Beyond apredetermined angle as zenith is approached the roll axis drive tohorizontal is gradually reduced in feedback strength and is graduallyreplaced with an ‘inertial only’ algorithm which tends to maintain thecurrent camera roll angle. Illustrative embodiments of the stabilizereither rely on the physical structure's passive roll inertia and furtheranticipate transitioning to a roll axis active inertial enhancementsimilar to that provided by described pan/tilt inertial enhancementalgorithms.

Specifically, for the roll axis, in reference to FIG. 5; the tilt axismeasured angle 350 b is applied to a function generator 327, which asshown produces a variable gain signal output 328, which reduces gain tozero as tilt angles approach zenith and 180 degrees away from zenith.Variable gain signal output 328 is applied to multipliers 323, 324reducing the roll torque feedback strength as zenith, anti-zenith anglesare approached.

Pan Axis Modification for Extreme Tilt Angles:

The pan axis algorithm as described is responsive to an earth orientedmeasure of pan rate and angle provided by the artificial horizonalgorithm. The measured earth oriented pan axis being substantiallyaligned vertically to local gravity. As a hand held or body carriedphysical structure, for example, is tilted to zenith the earth pan axisis no longer reasonably aligned with the camera's pan axis and indeedapproaches a 90 degree orthogonal relationship. Therefore, illustrativeembodiments of the invention, upon sensing a tilt angle beyond a set‘extreme’ threshold modifies the pan axis algorithm to be increasinglyresponsive instead to a measured angle and rate oriented to the camera'sown pan axis. Thus, the pan axis algorithm, at extreme angles of tilt,stabilizes the camera about its own pan axis and not an earth basedaxis. This may ‘unlock’ the pan axis from the strict earth basedpan-tilt mount model and its undesired gimbal lock behavior.

Indeed and of note it has been discovered that if the pan torquegenerator's axis is reasonably well aligned with the natural pan axis ofthe camera, a measure of pan rate and orientation may be continuouslyprovided to the pan axis algorithm from inertial sensors aligned to thecamera pan axis, rather than an earth-aligned axis. The arrangement maynaturally handle pan behavior for all angles of tilt including the‘through zenith’ tilt angle situation noted above without algorithmmodifications responsive to tilt angle.

To achieve the aforementioned pan axis modification, referring to FIG.4; the earth-referenced pan axis measured rate and angle 350 c, 350 dare replaced with camera-referenced pan axis measured rate and angle 210c, 210 d, respectively when measured tilt angle 350 b of FIG. 2 exceedsa selected threshold. Or if pan torque generator axis is reasonablyaligned with the camera's pan axis, the earth-referenced pan axismeasured rate and position 350 c, 350 d is permanently replaced withcamera-referenced pan axis measured rate and angle 210 c, 210 d andinput them to the pan axis algorithm of FIG. 4. More specifically, againreferring to FIG. 4, standard cross fade elements 348 c, 348 d areemployed to gradually replace earth-referenced pan axis measured rateand angle 350 c, 350 d with camera-referenced pan axis measured rate andangle 210 c, 210 d, respectively, as a function of measured tilt angle350 b as determined by function generator 348 f, which produces aselected cross fade fraction 348 e. The aforementioned cross fadeelements operate by multiplying a first input by the selected fractionof between zero and one and multiplying a second input by one minus theselected fraction and summing the two products.

Passive Trans-Gimbal Couplings

Further modifications can be made that enable single handed support plusorientation. An elastic coupling between an outer handle and innerassembly can provide a ‘soft end stop’ property which directs the camerapayload to smoothly accelerate angularly if the operator rotates thehandle beyond the gimbal's maximum angular range, particularly for theroll and tilt axes where limited angular range voice coils are typicallyemployed. An example of such devices can be found in U.S. patentpublication 2011/0080563A1, such devices as described, incorporatedherein by reference. An exemplary embodiment of the invention hasunlimited or near unlimited, pan angle rotation range, but an elasticcoupling across the pan axis has also been shown to productively allowone handed carrying plus orientation. The one-handed mode of operationis particularly useful when the operator's free hand is needed forsteering a vehicle or the like. The algorithms disclosed herein can beapplied to such an elastically coupled pan axis torque generator.

As previously described, illustrative embodiments of the invention mayenhance stability for operators of the stabilizing equipment directlyand locally controlling it hands-on. A remotely controllable variant,however, can be implemented producing the described stability featuresfor a remote camera platform.

In a first remote control application of the invention the typicalpassive remote control joystick or the like is employed. The joystick'ssignals are converted to represent torque commands and these transmittedcommands are summed with those already provided by the feedbackcontroller as previously described, the sums passed to the omni-axialtorque generator. As a result the joystick-based torque commands replacethose of a hands-on operator.

In a second remote controlled illustrative embodiment of the inventionthe aforementioned passive joystick or the like is replaced with a socalled ‘force feedback’, or ‘haptic feedback’ input device. Inillustrative embodiments of the invention the device is drivenreflectively in a powered fashion by actual camera orientation anglesprovided via feedback from the artificial horizon algorithm. A remoteoperator now has in hand a control surface with which to orient theremote platform mounted camera in a way that may closely resemble thatprovided for a hands-on operator of illustrative embodiments of theinventive stabilizer.

The described feedback controller 3 provides ‘supplemental’ torquesignals, one for each axis to be controlled through the final essentialsubmodule:

4: Omni-Axial Torque Generator:

The omni-axial torque generator subassembly is coupled to the omni-axialgimbal of the ‘sled’ of the stabilizer assembly 1, and responsive to the‘supplemental torque’ signals provided by the algorithmic feedbackcontroller 3.

The omni-axial torque generator is coupled between the supported side ofthe gimbal and the payload side. It couples orienting torques, throughthe gimbal, between the “sled” plus supported camera payload and thesupport side in parallel with those of the operator.

This subassembly may employ various methods and components but resultingtorques are preferably precisely controllable and uniform despite anyangular position of the gimbal. Candidate torque generators includeconventional permanent magnet DC motors driven by constant current poweramplifiers, and ‘voice coil actuators’ which may be single coilpermanent magnet DC motors that rotate less than a full turn.

In an exemplary embodiment of the invention, a chosen torque generatoror motor is attached to each rotatable joint of the gimbal so thattorques may be coupled between the stationary side of that joint and itsrotating side. The motors may be arranged so their weight does notunbalance the neutral balance of the assembly and the motor bodypositioning does not interfere with the operator's access to the controlhandle/guide.

Since feedback controller 3 develops correctional supplemental torquesreferenced to the camera payload's primary axes (pan, tilt, and roll),the omni-axial torque generator must take this into account. Some gimbalarrangements have axes of rotation that do not necessarily align withthose of the camera. Only the gimbal pan axis of this arrangement alignswith camera's pan axis. The other two axes of the gimbal instead alignwith the center of balance of the camera and all its counter-balancingmasses.

A first rotary joint attaches to the operator support, a second rotaryjoint, the axis of which is perpendicular to that of the first joint,attaches to the rotating side of the first joint and finally therotating side of second rotary joint attaches to the stationary side ofthe pan axis joint, the axis of which is substantially perpendicular toboth first and second joint axes, with the camera payload attached tothe rotating side of the pan joint. As the camera is panned its roll andtilt axes rotate with respect to the first joint and second joint axes.

Therefore, the supplemental correction torques produced by the feedbackcontroller 3 must be rotated the torques aligned to camera payload 110roll and tilt axes, and instead align them with the actual first joint,second joint axes. This is achieved by the feedback controller 3provided it receives the current angle of the pan joint via an attachedangle sensor generated signal.

For the handheld illustrative embodiment of the invention the order isreversed of the axis joints as is conventionally done. Referencing FIG.2, the stationary side of a roll axis torque generator 410 is attachedto the platform 120 with its axis substantially parallel to the camera'sroll axis. The rotor coil assembly 411 is attached to roll/tilt guide140, attached to tilt rotor coil assembly 421 of the tilt rotary joint,having an axis substantially perpendicular to that of the roll joint.Finally, the stationary side of the tilt axis torque generator 420 isattached to the rotating side of the pan torque generator output shaft431, the axis of which is substantially perpendicular to those of boththe roll and tilt joints, the pan rotary joint embedded in a pan axistorque generator that also serves as a handle 430 carried in theoperator's hand.

In this illustrative embodiment, the axes may be well enough alignedwith those of the camera that feedback controller 3 provided roll, tilt,and pan correctional supplemental torques may be applied directlythrough torque generators 4 attached to corresponding rotary joints ofthe gimbal without the need for rotary joint angle sensing.

In one such handheld illustrative embodiment, referring now to FIGS. 1and 2 omni-axial torque generator 4 is implemented for the roll and tiltaxes of the gimbal using voice coil motors for roll and tilt axistorques generators 410, 420 with the stator, rotor of each motorcorresponding to the stationary, rotary sides of the described roll,tilt axis joints. Finally, pan axis torque generator 430 is implementedwith a standard DC motor embedded inside the operator's hand carriedhandle that contains pan axis torque generator 430, the pan torquepassing between the handle and the connected tilt rotary joint 420attached to the remaining rig structure.

To further understand the gimbal arrangement of the roll and tilt axesfor the preferred handheld illustrative embodiment, refer to FIG. 6which shows an exploded view. As shown, the roll axis employs a rotaryvoice coil motor as a roll axis torque generator 410 with its stationaryor stator side fixedly attached to the camera side of the physicalstructure, and its rotor coil assembly 411 attached to right angle plate140 b. Shown within the rotor coil assembly 411 is a radial bearing 411a whose inner side is fastened to plate 410 a with a screw to the statorof roll axis torque generator 410 as shown. The outer side of thebearing 411 a within rotor coil assembly 411 is fixedly attached to thecombined assembly 411, 140 b, 421. The central axis of bearing 411 awithin rotor coil assembly 411 nominally or precisely coincides with thegimbal's axis of roll.

Similarly, the tilt axis employs a voice coil motor as a tilt axistorque generator with its stator side fixedly attached to the pan torquehandle assembly containing pan axis torque generator 430 pan torquegenerator output shaft 431 via coupling block 431 a. Tilt rotor coilassembly 421 is fixedly attached to the right angle plate 140 b. Shownwithin the tilt rotor coil assembly 421 is a standard radial bearing 421a whose inner side is fastened to plate 420 a with a screw to the statorside of tilt axis generator 420 as shown. The outer side of the bearing421 a within tilt rotor coil assembly 421 is fixedly attached to thecombined assembly 411, 140 b, 421.

The central axis of the outer side of standard radial bearing 421 awithin tilt rotor coil assembly 421 substantially coincides with thegimbal's axis of tilt.

By construction of the right angle plate 140 b the axes of roll and tiltand those of their respective bearings 411 a, 421 a intersect at or nearthe physical rig's 1 center of gravity. Furthermore, the axis of pan ispreferably coincident with the central axis of the pan torque handleoutput shaft 431 with the axis nominally or precisely passing throughthe intersection of the roll and tilt axes. Counterweight 431 bsubstantially balances the weight of assemblies 421, 420 such that theircommon center of gravity is substantially coincident with the axis ofpan, allowing the balanced component assembly center of gravitysubstantially coincident with the gimbal axes' intersection.

Operator control surface 140 a is attached to right angle plate 140 b.Control surface 140 a is for example a textured partial sphere with itscenter substantially coincident with the roll, tilt, pan axesintersection and the physical rig 1 center of gravity. Other types ofoperator control interfaces are within the scope of the invention.Various types of gimbals and other devices allowing analogous orcomparable degrees of freedom can also be implemented with methods andassemblies of the embodiments of the disclosure.

An operator may apply pan and tilt steering torques to the texturedsphere to orient the supported camera payload. As constructed, thecontrol surface 140 a of this handheld illustrative embodiment onlyallows operator orientation in the pan and tilt directions, as the rollaxis is automatically maintained level by the roll axis algorithm 320.

For the handheld illustrative embodiment, as described previously, panaxis torque generator 430 is implemented within the operator carryinghandle by employing for instance a common permanent magnet DC (PMDC)motor. By employing the PMDC motor as shown in the arrangement of FIG.7, substantially unlimited rotation of a pan rotary joint within anoperator carrying handle, likely allowing the operator to ‘walk around’the stabilizer to assume an optimum operating position without needingto re-grip the handle as the stabilizer continues to point in aparticular desired angular direction may be achieved.

Referring now to FIG. 7: The stator body of a standard PMDC motor 430 cor other suitable motor, is fixedly attached to pan torque generatoroutput shaft 431, the shaft maybe hollow as shown. Power wires 430 g,430 h for motor 430 c enter shaft 431 and exit the shaft as shown toconnect power to motor 430 c. A top end cap 430 b with embedded standardradial bearing 430 a freely rotates about shaft 431 while fixedlyengaging top end of handle shell 430 e. Finally a bottom end cap 430 ffixedly engages handle shell 430 e bottom end while motor 430 c outputshaft 430 d passes through a central hole in bottom end cap 430 fcentral hole and is fixedly engaged thereto.

Thus, the handle shell 430 e, carried in the operator's hand, isrotatable about the pan axis output shaft 431 without twisting the motor430 c power wires 430 g, 430 h.

Further illustrative embodiments of the invention provide alternative oradditional means to address bottom-heaviness of a balancing apparatus.Maintaining ‘level’ (the true correspondence of the sled ‘roll’ axis tothe local horizon), and ‘headroom’ (the necessary tilt angle to maintainthe desired shot), are two tasks that an operator generally desires toaccomplish. Both tasks are conventionally assisted by operating with thegimbal position adjusted to be centered slightly above thecenter-of-balance of the entire sled. Absent any significant lateralaccelerations, this results in slight bottom-heaviness. Bottom-heavinesstypically causes pendularity during lateral accelerations such asstarting, stopping or cornering; and any subsequently desired changefrom that nominal tilt angle is difficult to consistently maintain.

Nevertheless, the tilt and roll feedbacks from this electivebottom-heaviness are often taken to be so essential, that operatorslearn to apply the momentary angular counter-pressures required toneutralize pendularity. This typically takes significant skill.Illustrative embodiments of the invention provide an alternative meansto address this phenomenon.

A further illustrative embodiment of the invention provides a‘power-assisted gimbal’ replacement for conventional stabilizingapparatus gimbal assemblies, employing the substantiallyacceleration-proof angular detection methods and hardware as describedherein in other illustrative embodiments, coupled with a novel means forapplying appropriate assistive torques to at least two gimbal/yoke axes,despite the fact that the angles are likely to be variously andpersistently decoupled from the fixed sled axes of ‘roll’ and ‘tilt’.

Previously noted illustrative embodiments have substantially fixed axesof torque applied, unlike traditional stabilizing apparatus gimbalyokes, which are momentarily positioned anywhere around the axis of thesled center post, according to the demands of the shot, and any ‘torque’assistance applied to these gimbal axes must proportionally take thesediscrepantly shifting angular orientations into account for usefulcorrection. The further illustrative embodiment of the invention,various aspects of which can be used with other illustrative elements,therefore adds an optical, digital or analogue counter around the sled‘pan’ axis that tracks the momentary position of a conventionalstabilizing apparatus gimbal yoke, even as the operator moves his body,and thus the yoke, around the rig, from side to front to back, whileobtaining his or her shots. This pan-axis counter, along with anassociated new algorithm, therefore tracks the proportion between thesum and angular directionality of the gimbal torques as their momentaryrelationships vary with respect to the ‘roll’ and ‘tilt’ axes of theactual sled.

The counter hardware and software algorithms of this illustrativeembodiment of the invention track this angular relationship toappropriately power and vector the output of torque generatorsoperating, respectively, around the axis that is represented by theconventional yoke trunnion bearings (“tilt”) in the diagrams and theperpendicular axis of the yoke itself (“roll”) such as the bearing axis.This permits the sled to be neutrally balanced, and therefore,non-pendular—and yet still provides direct net torque assistance tomaintain level for the sled, and additionally maintain desired‘headroom’ by continuously powering the ‘tilt’ axis angle.

FIG. 9, which will be described in more detail below, shows the relativepercentage and direction of torque required for trunnion (“tilt”) motorsvs. yoke (“roll”) motors to continuously influence the roll axis to theright as the yoke moves 360° around the pan bearing. Note the centralarrows indicating the ‘forward’ direction for each iteration.

The percent allocation of the torques to the generators is a torquevector rotation. We want to rotate a roll, tilt torque vector referencedto the camera (or other payload being balanced) as produced by thealgorithms to a new roll, tilt torque vector aligned with the actualgimbal torque generators, which are attached to and aligned with theoperator side of the rig. The torque vector rotation is related directlyto the pan angle.

The standard equation for rotating a two dimensional (2D) vector, asrepresented in FIG. 8, is:X′=X*cos θ−Y*sin θY′=X*sin θ+Y*cos θwhere X, Y are desired supplemental torque signals from the algorithm tobe applied to payload aligned roll, tilt axes respectively. X′, Y′ areactual torques to be generated by the gimbal “roll” and “tilt” motors,respectively, attached to operator side roll, tilt gimbal axes,respectively. θ is an angular portion of a 360 degree measure of the panbearing rotation and is zero when gimbal “roll” axis aligns with payloadroll axis and gimbal “tilt” axis aligns with payload “tilt.”

The degree of pan bearing rotation can be sensed by any known methodcompatible with the apparatus and its use. Examples include: standardlinear potentiometer, sine cosine potentiometer, angular resolver(magnetic angle sensing using rotor and stator coils) and opticalencoder, both the relative type, for which an angular reset is typicallyrequired, and absolute type, which delivers an angle signal without anyreset means required.

Turning to FIG. 8, calculation of the actual torques to be generated bythe roll and tilt motors will be described. Block 502 indicates thesupplemental payload tilt torque value “Y” and block 504 indicates thesupplemental payload roll value “X”. Block 506 provides the pan shaftangle θ. Steps 508 and 510 show cosine θ and sine θ, respectively. Thepayload tilt torque value “Y” is multiplied by cos θ in step 512. Instep 514, the payload roll torque value “X” is multiplied by sin θ. Theresults generated in steps 512 and 514 are summed in step 516 to obtainthe actual torque Y′ to be generated by the gimbal tilt motor asprovided in block 518.

The actual torque to be generated by the gimbal roll motor is depictedby block 520 and obtained by the following steps: The supplementalpayload tilt torque “Y” from block 502 is multiplied by sin θ in step522. The supplemental payload roll torque “X” is multiplied by cos θ instep 524. In step 526, the result from step 522 is subtracted from theresult generated in step 524 to obtain the actual torque “X′” in block520.

If you plug in 0, 90°, 180°, 270° for 0 into the above equations youwill get the mix factors shown in FIGS. 9A, 9C, 9E and 9G, respectively.FIG. 9A depicts the mix factor values when the gimbal roll and tilt axesare aligned with the payload roll and tilt axes, +100% for the roll axisand zero for the tilt axis. θ=0 in this configuration so no adjustmentis needed. FIG. 9c depicts a configuration where θ=90°, whichcorresponds to factors of zero for the roll axis and −100% for the tiltaxis. FIG. 9E represents the configuration when θ=180°, wherein thefactors are zero for the tilt axis and −100% for the roll axis. At0-270°, the tilt factor is +100% and the roll factor is zero as shown inFIG. 9G. Additional increments of 90° from the initial 45° are depictedin FIGS. 9D, 9F and 9H, wherein the mix factors in FIG. 9D (θ=135°) are−70.7% for both the roll and tilt axes; the mix of factors in FIG. 9F(θ=225°) are +70.7% for the tilt axis and −70.7% for the roll axis; andthe factors for both the tilt and roll axes in FIG. 9H (θ=315°) are+70.7%. At 45° you obtain +70.7% for the roll axis, and −70.7% for thetilt axis, as represented in FIG. 9B. This makes sense as at 45° thetorque motors have less mechanical advantage and each needs more torqueto achieve the final algorithm-requested torque referenced to thepayload axes, now rotated 45° away from torque generator axes.

Since gimbal torques are applied 90° apart they are not additive butinstead obey a vector addition equation:T _(total)=√{square root over (T _(roll) ² +T _(tilt) ²)}wherein:1=√{square root over (0.707²+0.707²)}Utilizing the various calculations and apparatus described above, thetilt axis can be preset for a desired ‘headroom’ just as the roll axisis automatically preset to seek level.

FIG. 10 depicts an apparatus 600 for stabilizing a payload according toan illustrative embodiment, in which the methods described herein can beapplied. A handle 602 houses a pan motor 604, which can be seen in thetransparency view of FIG. 11 of an illustrative embodiment. Pan motor604 generates angular motion of a stage 610 about a pan axis 612. A tiltmotor 606 generates angular motion about a tilt axis 608 to tilt stage610 with respect to the longitudinal axis of handle 602. A roll motor614 rotates a roll frame 616 about a roll axis 618. Roll frame 616 canbe contoured to roll into a complimentary gap, such as in an outer frameor beneath stage 610. Pan, tilt and roll axes 612, 608, 618,respectively, converge generally at a grip 620 or roughly at or near thecenter of gravity of the apparatus 600 when containing a payloadpositioned on stage 610.

Grip 620 provides an operator control surface to enable a user tocontrol pan, roll and tilt motion by finger pressure. Preferably thismanual control can overcome the force of one or more of the motors. Whena user releases pressure on grip 620, the motors will hold the positionutilizing algorithms as described herein. Grip 620 can be designed tofloat “independently” and stay referenced to stage 610 or roll withhandle 602.

As shown by the illustrative embodiment depicted in FIG. 12, roll frame616 is fixedly attached to bosses 628, 630. Bosses 628, 630 arerotatable about tilt axis 608. Mounting 626 extends between bosses 628,630 and is fixedly attached to shaft 662 of a pan motor within handle602 so that mounting 626 is rotatable about pan axis 612, which isidentified in FIG. 11.

As shown in FIG. 10, sufficient clearance is present in areas 622, 624to facilitate use of grip 620, i.e. to provide room for a user's fingersto manipulate grip 620 to create movement about one or more of axes 608612, 618.

FIG. 13 depicts components of the tilt mechanism with parts of apparatus600 removed for better visibility. FIG. 15 provides additionalcomponents of the tilting mechanism; however, select parts are also notincluded for ease of understanding. Mounting 626 is rotatably attachedto tie rod link 634 at an end of mounting 626 opposing handle 602. Tierod link 634 rotates about axis 636 through pivot 638. A bell housing640 is rotationally attached to tie rod link 634 at pivot 642, which isat an end of tie rod link 634 that opposes mounting 626. Bell housing640 is further connected to the shaft of tilt motor 606, so as the shaftof tilt motor 606 rotates so too does bell housing 640 with respect totie rod link 634 at pivot 642, about axis 644, and in turn tie rod link634 rotates at pivot 638 about axis 636, and finally, mounting 626rotates about axis 608. The body of tilt motor 606 is attached to rollframe 616. As can be seen in FIG. 12, axis 608 is through bosses 628,630, which are bolted to roll frame 616, and thus, as tilt motor 606rotates bell housing 640, pan motor shaft 662 rotates with respect toaxis 608. Other mechanisms or components can be used for the samepurpose as bell housing 640, such as an additional link, which would beconnected between the tilt motor shaft and tie rod link 634. Turningback to FIG. 12, grip 620 is shown bolted to bosses 628, 630. Bosses628, 630 are bolted to roll frame 616 so grip 620 stays referenced toroll frame 616 and rolls with handle 602.

As shown in FIGS. 12 and 14 according to illustrative embodiments, a pin646 is disposed in slot 648 in roll frame 616. Pin 646 is fixedlysecured to an outer frame. As frame 616 rotates, the position of pin 646changes within slot 648. The relative excursion of pin 646 is limited bythe ends of the slot. This serves as a stop to limit the rotation ofroll frame 616. If it is desired for grip 620 to float independently andstay referenced to stage 610, grip 620 can be fixedly secured to pin646.

Outer frame 650 is connected to stage 610 and either directly or throughstage 610 to spar 652. Spar 652 is hinged to a second spar 654 at hinge656 to allow the apparatus to fold. A battery 660 or other componentassociated with a payload is located at or toward the end of spar 654. Aweight 658 can be used to balance apparatus 600 with a payload in placeon stage 610. Weight 658 can be adjustable, for example, by adding to oreliminating portions of the weight, or by advancement of the weightalong a threaded shaft. Placement of weight 658 can be directly situatedunder the intersection of axes 608, 618, 612 and parallel to thecamera-mounting surface on stage 610. In doing so, adjustment of weight658 vertically towards or away from the camera mounting surface on stage610 should not influence the overall balance of device 600 in the rollor tilt axis.

Advantageously, brushed motors can be used with illustrative embodimentsof the apparatus. Brushed motors with small gear ratios may beparticularly suitable for use with the apparatus. Illustrative ratiosinclude 4:1 or 10:1. Small gear ratios allow the motor to be back drivenrelatively easily by application of pressure to grip 620. Theartificially increased inertia provided by algorithms described hereinallow for use of brushed motors. Brushless motors typically produce muchmore torque for their size than same size brushed motor. Brushlessmotors generally suffer from magnetic cogging, which is an unwantedtorque coming through the motor shaft as it spins, even when unpowered.A very high loop bandwidth and fast response time can overcome thiscogging, but the payload is then held very stiffly by the feedbacksystem and consequently cannot be guided by direct contact to a grip asin illustrative embodiments of the invention. It is noted that brushlessmotors can be used in some illustrative embodiments of the apparatus.

FIG. 16 depicts another configuration of an actively stabilized payloadsupport apparatus 700 according to an illustrative embodiment of theapparatus. Support apparatus 700 has a grip 702 having a first gripsection 704 extending from the bottom of a second section 706. Secondgrip section 706 has a larger diameter than first grip section 704.First and second grip sections 704, 706 are generally cylindrical inthis illustrative embodiment. The outer surface of first grip section704 is substantially linear along its length unlike the grip 620 shownin FIG. 12 for example, which is curved. First grip section 704 can havea uniform diameter throughout or can be angled to varying degrees in aconical frustum configuration.

As shown in FIGS. 16 and 24, second grip section 706 has slots 708, 710,which accommodate roll frame 712 when roll frame 712 is rotated throughits excursion. Roll motor 714 is functionally connected to roll frame712 to impart rotational motion to roll frame 712. FIG. 19 shows rollframe 712 in a horizontal position. FIG. 16 shows roll frame 712 at anextreme of it excursion so it is disposed into slot 708.

Slots 708, 710 are generally arced slits in grip 702, such as shown inFIG. 16, for example for example. Grip 702 can be used on activelystabilized support systems such as shown in FIGS. 10-15, for example.The slotted grip configuration will likely be stiffer than thecantilevered version.

An illustrative upper limit of angular excursion range for payloadsupport apparatus 600 is about ±30° to about ±35°. An illustrative upperlimit of angular excursion range for payload support apparatus 700 isabout ±40° to about ±45°. Depending on specifications of various parts,such as grip diameter and the length of shaft 724 of the pan motorlocated in handle 726, the excursion of roll frames 616 and 712 canvary.

FIG. 17 depicts a portion of an actively stabilized payload supportsystem with grip 702 shown transparently, thereby revealing variouscomponents of pan, tilt and roll mechanisms and an illustrativefastening mechanism to secure grip 702 to stage 718.

Bolts 720, 722 are shown securing grip 702 to stage 718. Additionalbolts or other fastening mechanisms can be employed. Grip 702 is thusreferenced to stage 718 and moves independently from roll frame 712.This is a significant difference from grip 620 shown in FIGS. 10-15,which is referenced to roll frame 616.

Dimensions of exemplary grip 702 are now provided. An illustrative outerdiameter of first grip section 704 is 1.25 inches, and an illustrativeouter diameter range is about 1.2 inches to about 1.3 inches. Anillustrative length of first grip section 704, as measured from theopening of first grip section 704 to the interface with second gripsection 706, is about 0.40 inches to about 0.45 inches. The payload sizewill be one factor that will determine the optimum dimensions of variousparts of the payload support apparatus. The relationship of componentswill also have an effect on dimensions of parts and range of motion. Forexample, the positions of the bottom of grip 702, top of handle 726 andthe relative location of tilt axis 730, which relate to the length ofpan shaft 724, will have an effect on the maximum tilt excursion.

FIG. 16 shows handle 726 tilted with respect to grip 702. In FIG. 16,further tilting is limited by contact between handle 726 and grip 702.The position of tilt motor 732 and roll motor 714 can depart from thatwhich is shown in the figures. Alternative positions may be desired toavoid interference with other support apparatus components, or to betterbalance the system.

FIG. 18 is a cross-section of a portion of actively stabilized payloadsupport apparatus 700 according to an illustrative embodiment of theinvention. In FIG. 18, roll frame 712 is in a non-horizontal position.Tilt motor 732 is attached to roll frame 712, so rolls with it. Grip 702is referenced to stage 718 so does not roll with roll frame 712.Mounting 734 is disposed between bosses 736, 738, which are attached toroll frame 712. Mounting 734 is further attached to pan shaft 724.

FIG. 20 depicts a view looking up through the bottom of grip 702according to an illustrative embodiment of the invention. Handle 726 isangled in this view but extends directly below grip 702 in a non-angledmode. Slots 710, 742 accommodate roll frame 712 as it rolls in a firstdirection away from the horizontal position, and slot 708 and a slotopposing slot 742 (not shown) accommodate roll frame 712 as it rolls inthe opposite direction away from the horizontal position. Furthervisible in FIG. 20 are bosses 736, 738 and mounting 734 disposed betweenthe bosses.

FIG. 19 depicts a scalloped-edged grip 744 having a smaller diametergrip section 746 and a larger diameter grip section 748 according to anillustrative embodiment. Two opposing portions 750, 752 of largerdiameter grip section 748, together with interspersed, extended smallerdiameter portion 754, and an opposing extended portion, form slots intowhich roll frame 712 can rotate. Smaller diameter grip section 746 isnot stacked with larger diameter grip section in the manner of grips 620and 702, i.e. with all points of an interface in the same plane.Instead, portions of smaller diameter grip section 746 extend up tolevels at which larger diameter grip section 748 is present, such asportion 754 of smaller diameter grip section 746. A second smallerdiameter grip portion exists opposite grip portion 754 (but is notvisible), and also extends to a level in common with portions of largerdiameter grip portion 748. Smaller diameter grip portions extending tolevels of larger diameter grip section 748 provide additional gripsurface area for an operator to utilize when controlling the apparatus.This can compensate for reduced surface area resulting from reduction inmaterial at the lower edge of grip 744 to the form a scalloped edge 756.In an illustrative embodiment of the invention, the diameter of smallerdiameter grip section 754 is approximately 1.3 inches, with anillustrative range of about 1.25 inches to about 1.35 inches. Anillustrative diameter of pan shaft 760 is about 0.25 inches.

FIGS. 20-21 demonstrate the function of scalloped-edge 756 of grip 744.FIGS. 20 and 21 show handle 726 tilted toward grip 744. FIG. 21 showsthe point at which pan shaft 760 encounters grip 744. An indentation 758in scalloped edge 756 provides space to accommodate pan shaft 760 as itis tilted upward toward grip 744. Three additional indentations spacedevenly around scalloped edge 756 allow pan shaft 760 to be tilted at agreater angle than if no indentations were present. The indentations arecut-outs in the scalloped edge 756 of grip 744. Other numbers,configurations and distributions of the cut-outs can be used providedthey allow the achieve the desired function and extent of accommodatingpan shaft 760.

FIG. 20 provides a view of the universal joint 798 providingperpendicular axes of rotation, one around roll axis 731 and one abouttilt axis 730. As pan shaft 760 tilts about tilt axis 730, and stage 718rolls about roll axis 731, the four indentations 758, 764, 766, 768 inthe bottom of scalloped edge 756 provide room for pan shaft 760 toextend into grip 744 to increase the degree of possible tilt compared tothe tilt limit of a straight-edged grip. The center of indentations 758,764, 766, 768 are positioned at the midpoint angle (i.e. 45°) of eachquadrant formed by the two axes of universal joint 798, tilt axis 730and roll axis 731. This midpoint represents the excursion produced whenboth joints are exercised equally, thereby maximizing the angle ofhandle 726 from the vertical.

FIG. 21 shows the following features of grip 744 that were describedabove: indentations 758, 764, 766, 768; larger diameter grip portion752; smaller diameter grip portion 754; and scalloped edge 756.

FIGS. 22-24 depict an actively stabilized payload support apparatusaccording to a further illustrative embodiment of the invention. FIG. 22shows a portion of the apparatus with grip 778 shown transparently toexpose gimbal components and connection of grip 778 to various parts ofthe apparatus. Grip 778 is referenced to stage 718 by being fixedlysecured with bolts 770, 772, on one side and additional bolts on theopposite side (not shown). Large diameter grip section 748 of grip 778,shown transparently in FIG. 22, and an opposing grip section are of athickness sufficient to accommodate bolts 770,772 and any additionalbolts used to secure grip 778 to stage 718.

As can be seen in cross sectional FIG. 23, grip 778 is further securedto boss 782 via bearings 784, 786, thereby providing a roll axis 788.Boss 782 is secured to roll frame 712 by bolts 790, 792, 794, of which790 is visible in FIG. 22, and an additional bolt not shown, althoughother fastening mechanisms or configurations may be used. FIG. 27depicts an illustrative boss 782 having four holes 791, 793, 795, 797through which bolts 790, 792, 794 and one additional bolt are disposed.Boss 782 also has openings 802, 804, 806, 808 to accommodate universaljoint 798, with one axis of rotation passing through openings 802, 804and a second, substantially perpendicular axis, passing through openings806, 808.

The illustrative embodiment depicted in FIG. 23 differs frompreviously-described configurations because roll frame 712 terminatesand is supported inside grip 778 by bearings 784, 786, placing the rollaxis through grip 778. FIG. 23 also shows pan axis 762 and tilt axis730.

FIG. 24 is a cross section of the actively stabilized payload supportapparatus of FIGS. 22 and 23. Since roll frame 712 is secured to boss782, which in turn are secured to grip 778, roll frame 712 need notextend on both sides of handle 726 for support. As can be seen in FIG.24, roll frame 712 need only extend toward roll motor 714. Further seenin FIGS. 22-24 is pan shaft 760, which is secured to grip 778 so thatgrip 778 exhibits pan motion produced by a pan motor 796 that iscontained in handle 726.

FIGS. 25 and 26 depict an actively stabilized payload support accordingto an illustrative embodiment in which, similar to the illustrativeembodiment shown in FIG. 23, has a grip 779 referenced to stage 718.Grip 779 is secured to boss 782 via a single bearing 776. This isdifferent from the illustrative embodiment shown in FIG. 23 in whichgrip 778 is secured to boss 782 via two bearings 784, 786.

FIG. 28 depicts a portion of an actively stabilized payload supportapparatus 800 with grip 802 presented transparently to show a pinion andsector gear mechanism 804 that produces and controls roll and tiltmotions, according to an illustrative embodiment of the disclosedapparatus. FIG. 29 depicts pinion and sector gear mechanism 804. Sectorroll gear 806 generates roll motion and sector tilt gear 808 createstilt motion. Motor 812 drives sector tilt gear 808 via tilt pinion 816.Motor 814 drives sector roll gear 806 via pinion 818. Grip 802 has anextended section 810, for example, to accommodate circuitry.

FIGS. 30 and 31 depict a perspective and side view, respectively, ofactively stabilized payload support 800 according to an illustrativeembodiment of the disclosure apparatus. Imaging device 820 is secured tothe payload support by holder 822. Holder 822 is moveable with respectto grip 802 as shown by arrows 830 on FIG. 31. As shown in FIG. 32,movement may be adjustable for example, by a screw 854 and threadedreceiving component 856, with screw advancement controlled by a knob852. The position of imaging device 820 and holder 822 with respect tocenterline 824 of the apparatus affects the balance of the system.Centerline 824 is a virtual vertical line that extends through thecenter of gravity of the apparatus. Typically, a user will wantcenterline 824 to be coincident with the vertical centerline of imagingdevice 820, both front to back, and side to side. The apparatus andassociated payload will be set up so centerline 824 passes through thelongitudinal axis of handle 834 and the single convergent point of thetilt, roll and pan axes. Holder 822 though adds weight to one side ofthe imaging device. This may be offset by a number of componentsdistributed about the center of gravity that further affect the system'sbalance. Extended grip section 810 as depicted offsets the opposingweight of spars 826, 828. Only one set of spars is shown in FIG. 31.Opposing spars 840, 842 are present in the apparatus as shown in FIG.30, for example. Battery case 832, which in an illustrative embodimentholds three double A batteries, may be in line with centerline 824, oron either side. Extension 838 serves as a weight, which may bepermanently affixed at a specific location. Alternatively, extension838, or other form of weight, may be added or removed as necessary tofurther affect the desired balance of the apparatus. In an illustrativeembodiment, extension 838 counterbalances spars 826, 828, 840, 842 theunloaded support apparatus, i.e. without batteries in battery case 832and imaging device 820.

Support apparatus 800 can be folded for storage as shown in FIG. 32.Referring to FIGS. 28, 32, and 33 a slot 836 is shown in grip 802. Whenhandle 834 of payload support apparatus 800 is folded upward, pan shaft844 is accommodated in slot 836. Spars, 826, 828 are fold toward eachother and further toward handle 834. Similarly, spars 840, 842 foldtoward each other and further toward handle 834 so that handle 834 isbetween spars 826, 828, 840, 842, as depicted, for example, in FIG. 32One or more cross pieces (not shown) can be incorporated between thesets of spars to serve as a stop for handle 834 when folding theapparatus. A cross piece would extend, for example, between spars 826and 840.

As shown in FIG. 33, tilt sector gear 808 disengages from tilt pinion816 when the apparatus is folded. The relative positions of tilt sectorgear 808 and slot 836 are designed to ensure that tilt sector gear 808disengages from tilt pinion 816 when handle 834 is folded upward.

As depicted in FIG. 32 holder 822 folds toward spars 826, 828, 840, 842by pivoting about axle 846. As can be seen, for example, in FIG. 34holder 822 has a clip 848 that secures imaging device 820 to payloadsupport 800 when the apparatus is unfolded. Clip 848 is preferablyspring-loaded, but alternative mechanisms can be used to securely engageclip 848 with imaging device 820 in the desired position. When holder822 is in a folded position, clip 848 is in the vicinity of battery case832. Battery case 832 has a clip-engaging component to secure batterycase 832 in place when the payload support is folded. The clip-engagingcomponent can have a variety of configurations, as long as it engagesclip 848 to secure the apparatus in a folded position.

In a further illustrative embodiment of the invention, the handle is notfolded up, but instead remains ‘vertical’ and other components foldtoward or ‘inline’ with the handle.

FIGS. 35-39 depict a further illustrative embodiment of an activelystabilized payload support apparatus 900, which may include componentsof the other illustrative embodiments shown or described herein. FIG. 35is a perspective view of actively stabilized payload support apparatus900 looking down into a stage body 902. FIG. 36 is a side view of anillustrative embodiment. FIG. 37 is a back view of actively stabilizedpayload support apparatus 900. FIG. 38 is a cross-sectional view throughline A-A of FIG. 37. FIG. 39 is a close up perspective view of themechanism within stage body 902. FIG. 40 is a close-up cross-sectionalview of the mechanism within stage body 902.

Actively stabilized payload support apparatus 900 includes a stage body902 having a grip 904 attached thereto or integral therewith. Stage body902 can be configured in numerous ways, provided that it is associatedas necessary with other components of the apparatus, such as for examplewithout limitation, pivot shafts 935, 936, and can be configured toallow support of a payload thereon or in conjunction with. Stage body902 and grip 904 surround a tilt sector gear 928 and a roll sector gear942 that impart roll and tilt motion to a payload supported by orsecured to actively stabilized payload support apparatus 900. Sectorgears 928, 942 are attached to or integral with frame 958. Frame 958 canhave various configurations provided it allows for the necessaryrotation about the associated axes. It can be for example, considered asa section of a gimbal apparatus, and may for example take on the formof, or replace, a gimbal yoke. Handle 906 surrounds a tilt motor 908 anda pan motor 910. The bodies of tilt motor 908 and pan motor 910 do notrotate relative to grip 904.

Tilt motor 908 is attached to tilt motor drive shaft 924. A tilt axisdrive gear 926 is attached to tilt motor drive shaft 924. Tilt axisdrive gear 926 is functionally engaged with tilt sector gear 928. Tiltsector gear 928 is attached to or integral with frame 958. Frame 958 ispivotally attached to main support shaft 934 at tilt axis pivot 930, 932allowing frame 958 to rotate with respect to main support shaft 934about tilt axis 918. Frame 958 is further attached to stage 902, at rollaxis pivot shafts 935, 936, or other suitable attachment mechanism. Astilt axis drive gear 926 rotates it causes tilt sector gear 928 torotate, and hence, frame 958 and stage body 902 are tilted about tiltaxis 918 in a plane perpendicular to the rotation of tilt axis drivegear 926. A payload secured to stage body 902 would thus also rotateabout tilt axis 918.

A roll motor 920 rotates a payload secured to actively stabilizedpayload support apparatus 900 about roll axis 922. Roll motor shaft 938is connected to roll axis drive gear 940. Roll axis drive gear 940 isfunctionally engaged with roll sector gear 942. Roll sector gear 942 isattached to or integral with frame 958. Frame 958 is connected to stagebody 902 by rotational components, such as roll axis pivot shafts 935,936. Thus, a payload attached to stage body 902 will rotate about rollaxis 922 when roll motor 920 imparts angular motion to roll axis drivegear 940, and hence roll sector gear 942.

Pan, tilt and roll axes 916, 918, 922, respectively, converge generallyat a grip 904 or roughly at or near the center of gravity of theactively stabilized payload support apparatus 900 when containing apayload positioned a stage supported by stage body 902, or other stagestructure.

Tilt motor 908 is coupled to pan motor 910 by a concentric motor coupler912. Pan motor shaft 914 is grounded to handle 906. Bearings 946, 948allow relative rotation between handle 906 and main support shaft 934.Because pan motor shaft 914 is grounded to handle 906 pan motor shaft914 generates angular motion of stage body 902 with respect to handle906 about a pan axis 916.

FIG. 41 is an exploded view of actively stabilized payload support 900.FIGS. 42 and 43 are enlargements of portions of FIG. 41. Shown in FIGS.41-43 is handle 906, into which tilt motor 908, coupled to pan motor 910by concentric motor coupler 912, are inserted. Tilt axis drive shaft 924extends from tilt motor 908 through cap 950. Cap 950 is threadedlyengaged with handle 906. Main support shaft 934 is disposed around tiltaxis drive shaft 924 and through cap 950. Stage body 902 and attachmentcomponents, roll axis pivot shafts 935, 936, which attach stage body 902to frame 958 are also shown. Tilt axis drive shaft 924 is disposedthrough bearings 946, 948 at or near the top of handle 906. Main supportshaft 934 is further disposed through bearing 954 within stage body 902.

Wire routing openings 956 a,b,c,d are provided to thread wires throughfor operation of the motors and any other electronic components. Anynumber of openings suitable for the structure and use may be included.

FIG. 44 is a back view of a further illustrative embodiment of anactively stabilized payload support apparatus. FIG. 45 is across-sectional view through line A-A of FIG. 44 showing frame 958tilted back at an angle α. Slot 964 accommodates the main support shaft934, which may be required in this tilted configuration, particularlywhen the apparatus is folded. An illustrative angle α is shown in FIG.45, wherein the angle is formed roughly between a line through rollpivot shafts 960, 962 and a line through a roll motor shaft 972. In anexemplary embodiment, angle α is in the range of about 10° to about 20°.

A roll motor shaft 972 turns a roll axis drive gear 966. Roll sectorgear 968 is tilted in this embodiment, so without change to theorientation of roll axis drive gear 966, one or both of the componentsmust be modified so they functionally engage, such as by being beveled.FIG. 46 is a close up perspective view of a portion of sector gears 968,970 of the FIG. 45 embodiment in which the angle of the gears withrespect to one another is shown.

Roll pivot shafts 960, 962 interface with tilted stage body 976 atdifferent points than those in a non-tilted version to accommodate thetilted configuration.

FIGS. 47 and 48 depicts a further illustrative embodiments of anactively stabilized payload apparatus. The apparatuses have a gimbal 978with a first gimbal axis 980 and a second gimbal axis 982, wherein thefirst gimbal axis is substantially perpendicular to the second gimbalaxis. The gimbal is also rotatable about a pan axis coincident with thelongitudinal centerline of pan shaft 988. The pan axis is mutuallyperpendicular to first gimbal axis 980 and second gimbal axis 982.Gimbal 978 has a yoke 992 pivotably attached to a gimbal pan bearingcomponent 994 for rotation about second gimbal axis 982, wherein yoke992 is attached to gimbal pan bearing component 988 at a first pivotshaft 996 and a second pivot shaft 998 opposing the first pivot shaft996.

FIG. 47 depicts an illustrative embodiment with co-axial or omnitorque-generators having direct drive motors to produce angular motionabout first gimbal axis 980 and second gimbal axis 982. A first torquegenerator in the form of a motor 984 is disposed at yoke stem 1000 andproduces rotational motion about first gimbal axis 980. Second torquegenerators in the form of motors 986 a,b produce rotational motion aboutsecond gimbal axis 982. In this embodiment, one of each motors 986 a,bis disposed on either side of pan shaft 988 at the connection of yoke902 to gimbal pan bearing component 994.

FIG. 48 depicts an illustrative embodiment with co-axial or omnitorque-generators comprising a first gear 1006 in the form of a sectoror arc gear, driven by a functionally connected drive gear rotated bymotor 986 c to produce angular motion about second axis 982. A secondarc or circular gear 1008 is functionally connected to a drive gearrotated by motor 984 to produce rotation about first gimbal axis 980. Apan axis counter 990 may be used to track the angular position of gimbalyoke 992, even as the operator moves his body, and thus yoke 992, aroundthe rig, from side to front to back, while obtaining his or her shots.Pan axis counter 990 provides angle θ, which is input to a processingdevice containing computer code to carry out an algorithm, such as willbe described further below. Pan axis counter 990 tracks the ratiobetween the sum of the gimbal torques and the and angular directionalityas their relationships vary with respect to the first gimbal axis orsecond gimbal axis of the actual sled, which may be ‘roll’ and ‘tilt’axes, for example.

Engagement of motors 984 and 986 a, b, c to adjust the apparatus aboutfirst gimbal axis 980 and second gimbal axis 982 can be by means otherthan the gears depicted, provided they are compatible with the supportapparatus structure and use.

FIG. 47 further depicts an arm post socket 1004 attached to or integralwith stem 1000 and configured for attachment to a counterbalancing arm,such as for example an equipoising arm. The counterbalancing arm mayinclude a parallelogram link with a resilient member to counter theweight of the support apparatus and a payload support thereby.

In an exemplary embodiment, one or more torque generators on theapparatuses are brushless motors.

Various embodiments of an actively stabilizing payload supports havebeen described that can containing sensors. The associated sensors canbe located in various positions depending, at least in part, on theconfiguration of the payload support and the methods and algorithmsused. In an exemplary embodiment, an angular sensing unit (IMU) isco-located with the camera or other payload, with the IMU roll, tilt,pan angular sensing means co-axial with and responsive to the camera'sroll, tilt, pan axes of rotation, respectively.

In a further illustrative embodiment the IMU is attached to the gimbal'souter pan bearing support with a first angular sensing means responsiveto the trunnion axis angle, a second angular sensing means responsive toan axis substantially perpendicular to both the trunnion axis and panpost axis, said means substantially responsive to the yoke axis angle,and a third angular sensing means responsive about an axis parallel withthe pan post. Note though that sensors need not be in a single unit butcan be separate sensors disposed at different locations from oneanother.

A rotation measuring device 990 is functionally installed in the payloadsupport apparatus to measure an angle θ of rotation of the pan shaft.One or more processing devices are configured to receive angle θ. One ormore non-transitory storage devices on which is stored executablecomputer code are operatively coupled to the one or more processingdevices and execute computer to carry out the method comprising:

receiving angle θ from the rotation measuring device;

calculating cosine θ and sine θ;

receiving a selected supplemental roll torque;

receiving a selected supplemental tilt torque;

adding the product of the supplemental payload tilt torque and cosine θto the product of the supplemental payload tilt torque and sine θ toobtain a second gimbal axis torque;

subtracting the product of the supplemental payload first torque andsine θ to the product of the supplemental payload first torque andcosine θ to obtain a first gimbal axis torque;

causing the second torque generator to generate the second gimbal axistorque; and

causing the first torque generator to generate the first gimbal axistorque.

In an illustrative embodiment, angle θ equals zero when first gimbalaxis 980 aligns with a payload roll axis and second gimbal axis 982aligns with a payload tilt axis. The zero reference though can becalibrated to be referenced to other suitable configurations of thegimbal axes.

The illustrative embodiments of the support and orienting apparatus andmethods disclosed may include some or all of the following features:

-   -   a) supplemental counter torques applied to the payload through a        gimbal while remaining responsive to direct operator contact to        guide and orient a supported balanced expanded payload;    -   b) direct operator control of an actively stabilized three axis        platform wherein a three axis apparatus is not touched directly        by an operator during actual use, and is remotely steered        electronically by an operator employing a remote control        interface, such as a joystick or the like;    -   c) increase in the moment of inertia of the supported expanded        payload without adding weight, spinning flywheels, or increasing        the size, the inertia increased by providing supplemental        counter torques to the expanded payload through the gimbal, the        torques being proportional to and in opposition to external        torques intentionally applied by the operator or through        disturbances;    -   d) a dynamic friction referenced to a stationary inertial frame        producing a resistive feedback torque which increases with        angular rate and is felt by the operator as the operator applies        torque to rotate the orientation of the expanded payload. The        dynamic friction as desired damps excessive operator torque        impulses and external disturbances such as wind friction;    -   e) a static frictional torque feedback, referenced to a        stationary inertial frame, such that when a particular pan and        tilt orientation is achieved by direct operator control and the        device is stationary, it will tend to maintain that orientation        once the operator has released control of the operator control        surface attached to the payload and even when slightly        unbalanced or disturbed by an external force;    -   f) feedback torques through the gimbal to the expanded balanced        payload, the torques directed to align the payload's axis of        tilt to be substantially parallel to the local horizon, or        equivalently, perpendicular to a measure of the direction of        gravity, even as the operator continues to apply pan and tilt        torques to orient the payload; and    -   g) application of the supplemental torques described above such        that the stabilizer operates relatively unobtrusively.

The invention includes a method of stabilizing a balanced componentassembly such as those described herein, having a plurality of torquegenerators. In an illustrative embodiment of the invention, the methodincludes the following steps:

-   -   a) using an angular motion sensing unit measuring and providing        angular rates and orientation motions of the balanced component        assembly about three substantially mutually orthogonal axes,        wherein such angular rates and orientation motions include that        which is produced by operator input and external disturbances;    -   b) providing a physical model comprising desired angular rates        and orientation motions for the three substantially mutually        orthogonal axes;    -   c) comparing using a signal processor the measured angular rates        and orientation motions to the modeled angular rates and        orientation motions, respectively, for each of the three        substantially mutually orthogonal axes, to create a comparison        for each of the substantially mutually orthogonal axes;    -   d) generating a supplemental torque signal for each of the        substantially mutually orthogonal axes based on the respective        comparisons;    -   e) applying each of the supplemental torque signals to a        respective torque generator;    -   f) repeating step (a) through (e) to form a feedback loop.

The three mutually orthogonal axes may correspond to pan, tilt and roll,for example. Separate algorithms may be used for each of thesubstantially mutually orthogonal axes to create a comparison of themeasured angular rates and orientation motions to the modeled angularrates and orientation motions. The supplemental torque signal mayincreases the angular inertia of the balanced component assembly.

Static torque and frictional torque referenced to a fixed inertial framemay be added to the modeled tilt torque and modeled pan torque of thephysical model. The moment of inertia and coefficient of dynamic brakingfriction may be automatically reduced over time as a function ofincreasing measured angular rate about each substantially mutuallyorthogonal axis.

The method may include providing a threshold torque below a supplementaltorque limit and reducing the supplemental torque when the externaltorque reaches the threshold torque, thereby signaling an operator toreduce operator torque input. When the external torque departs from thethreshold torque, supplemental torque is re-applied.

The invention includes: a gyro-stabilizing Steadicam-type gimbalreplacement assembly comprising:

-   -   level and tilt sensing means located remotely on the ‘sled        stage’;    -   pan-angle sensing means (as detected between inner and outer        races of gimbal pan bearing) located on the gimbal assembly;    -   means for motorizing the gimbal trunnion assemblies to influence        the gimbal yoke to center post angle;    -   means for coaxially motorizing the gimbal yoke bearing shaft        assembly to influence the angular relationship between an arm        post and the gimbal yoke shaft; and    -   computational means (located on either the stage or the gimbal)        to integrate the essentially perpendicular influences of        trunnion and yoke motors according to the momentary gimbal angle        in order to cause the Steadicam ‘sled’ to seek level and        simultaneously preserve the selected tilt angle in spite of the        operator's changing position—on either side or behind—his or her        equipment.

Illustrative embodiments of the invention include an apparatus forstabilizing a payload comprising a rig having an omni-axial torquegenerator comprising a roll torque generator, a tilt torque generatorand a pan torque generator; a feedback controller; the omni-axial torquegenerator driven by a supplemental torque output signal generated by thefeedback controller; an angular motion sensing unit capable of measuringangular rates and orientation motions produced by the omni-torquegenerator wherein the angular rates and orientation motions include thatwhich is produced by operator-input and external disturbances; thefeedback controller having a signal processor functionally connected tothe angular motion sensing unit to receive as an input the measuredrates and measured orientations. The signal processor includes anartificial horizon algorithm, a roll axis algorithm, a tilt axisalgorithm and a pan axis algorithm. The signal processor, by therespective algorithms, is capable of processing the measured angularrates and orientation motions to produce the supplemental torque signalsto be applied to each of the pan, tilt and roll axis, which when appliedmodify the angular rates and angular positions to conform to a physicalmodel.

The electronic structure and related mechanical structure can includeany of the handles and related mechanisms to impart roll, tilt and panto the payload supported by the apparatus.

The apparatus may have an operator-control surface for controllingmotion about the pan axis and the tilt axis, wherein motion about theroll axis is controlled by the feedback controller only.

The stabilization techniques, methods and theories of embodiments of thecamera stabilization system can be applied to larger stabilizationsleds, but there are some differences.

Conventional “sleds,” such as those marketed under the name STEADICAM®sold by The Tiffen Company, rely on the relatively large masses of thecamera, monitor, and batteries to generate inertia for angularstabilization of the image. These sleds also use these masses to balancethe sled to hang upright from a very low friction three-axis gimbal. Inorder for the sled of these larger systems to hang upright, its centerof gravity must be below the supporting three-axis gimbal. With atypical sled, when it is so balanced and is moved, the sled behaves likea long pendulum and the image goes off level unless the operatorintervenes. One of the basic skills of camera stabilization systemoperating is to anticipate this pendular action and prevent it fromhappening. The more the center of gravity is situated below thesupporting gimbal, the stronger the pendular effect and the more work anoperator has to do to prevent it.

If the operator balances the sled with the center of gravity close tothe supporting gimbal, the pendular effect and consequent preventionefforts, are reduced, but with a loss of tactile feedback for what islevel, which can be a challenge to the operator. The operator mustconcentrate more and more on keeping the frame level without any tactilefeedback, whether or not the camera stabilization system is moving inspace.

What is desired is a neutrally balanced, naturally inert sled thatartificially creates vertical positioning and operator feedback. Thesled will create the feeling of a classically balanced camerastabilization sled, but can be balanced and operated with reducednegative pendular consequences nor the loss of horizon, freeing theoperator to concentrate more on artful framing.

FIGS. 49-54 depict illustrative embodiments of the disclosed camerastabilization system, which include a number of sensors and motors thatattach to a camera stabilization sled 1100 having a three-axis gimbal1102. FIGS. 55-59 depict an electronic control unit to implement thesystem processes according to illustrative embodiments. In anillustrative embodiment the sensors include three angular rate sensors1104, 1106, 1108, three accelerometers 1110, 1112, 1114, and a pancounter 1116.

The sensors may be in an enclosure 1120 aligned or fixed to a camera1122 on top of sled 1100. Flexible wiring may connect the sensors to agimbal yoke 1124 of gimbal 1102. Two main motors 1128, 1130, gimbal yokeaxis motor and trunnion motor, respectively, are attached to a supportarm 1132 locked to gimbal yoke 1124, and are oriented at 90 degrees fromone another. A third motor 1118 can also be employed that may double asa pan counter. Third motor 1118, if employed, acts parallel to the “pan”axis 1136 and provides additional “leveling” torque when thestabilization sled 1100 is tilted up or down. Via adjustable belts andpulleys, motor 1128 acts to drive gimbal 1102 rotationally around aplane at 90 degrees to a support handle 1134. Motor 1130 acts on theaxis of the trunnions.

Pan counter 1116 is used because camera 1122 and sensors 1110, 1112,1114 that determine level are not fixed relative to gimbal supporthandle 1134, so neither of motors 1128, 1130 is necessarily aligned tocamera roll (level) or to camera tilt. Pan counter 1116 keeps track ofthe pan rotation about pan axis 1136, or orientation, between camera1122 and motors 1128, 1130, so the appropriate corrections to bothmotors will keep sled 1100 level with respect to camera 1122 or at thedesired angle.

In an exemplary embodiment, components of camera stabilization system1100 are readily removable or attached to a standard, and possiblyunmodified, gimbal 1102. Support arm 1132 for motors 1128, 1130 isattached to gimbal yoke 1124 via a single cap 1138 that screws into oneof two trunnions 1140, 1142. Gimbal trunnion driven pulley 1144 battaches via a screw to the opposite trunnion. The gimbal yoke axisdriven pulley 1148 b attaches via set screws to gimbal support handle1134. A magnetic sensor 1158 for pan counter 1116 is attached via abracket 1152 and screws to the outer race 1154 of the pan bearing 1156.

The system may be configured to be small enough to remain attached togimbal 1102 for “normal” operating and also for storage in a standardcase.

Gimbal trunnion pulley 1144 connects to the gimbal's outer pan bearingrace 1154. A screw connecting to bracket 1152 on outer pan bearing race1154 prevents gimbal trunnion pulley 1144 from turning relative to outerpan bearing race 1154.

Pan counter 1116 comprises a pan counter sensor 1158 attached to outerpan bearing race 1154, and a reference ring 1160 attached to the aninner race 1155 of pan bearing 1156, which is locked to the cameraorientation. The pan counter sensor 1158 and reference ring 1160 shownare magnetic, but the pan counter system could be optical,electrostatic, or mechanical. Typically, in a two-motor configuration asystem other than a mechanical system is preferred due to additionalfriction, but use of a mechanical system cannot be ruled out.

A mechanical connection (either a spur gear train or a belt and pulleysystem) may be used if pan counter sensor 1158 is part of a system usingthird motor 1118 situated to drive sled 1100 around pan axis 1136. Thirdmotor 1118 may be desired when sled 1100 is tilted up or down more than25 degrees from horizontal or so. See for example FIGS. 53 and 54. Themore camera 1122 is tilted, keeping it level to the horizon becomes moreand more a function of pan bearing 1156. Having a motor acting on panaxis 1136 may be more efficient than driving motors 1128, 1130. Ifcamera 1122 is pointed directly up or down, pan axis 1136 will generallybe 100%, or near 100%, oriented to camera level.

Typically, when camera 1122 is pointed radically up or down, forexample, as shown in FIG. 53, locking camera 1122 to the horizon becomesless and less important. In a two motor configuration as shown, methodscarried out by electronic control unit 1162 and the associated sensors,may be implemented to reduce and eventually cut off the effect of motors1128, 1130 as sled 1100 is increasingly tilted.

The operator can, if desired, force sled 1100 off level. If wildlyoff-level shots are desired, the operator can temporarily disable thesystem causing sled 1100 to behave more like a conventional sled.

FIG. 55 depicts an illustrative electronic control unit (ECU) 1162 thathouses the electronics to control camera stabilization system 1100.Referring to FIG. 58, ECU 1162 houses one or more processors 1180operatively coupled to one or more non-transitory storage devices 1182on which is stored executable computer code, which when executed by theone or more processors causes the system to carry out the methodsdescribed herein to stabilize the camera and sled apparatus. Computerreadable media contain code that can be implemented by the system'sprocessor(S) to carry out the desired steps, and may be, for example,volatile and non-volatile, removable and non-removable media, includingbut not limited to ROM, PROM, EPROM, EEPROM, RAM, SRAM, DRAM and flashmemory.

Sensors 1104, 1106, 1108, 1110, 1112, 1114 1116 are in communicationwith input/output sub-system or bus 1198. Also in communication with bus1198 is memory 1182 and processor 1180. Memory 1182 and processor 1180may include multiple processors and memory devices, but are used hereinin the singular for simplicity. Bus 1198 is further functionallyconnected to motors 1128, 1130 and, optional, third motor 1118.

A user interface, for example, in the form of interface panel 1164,shown in FIGS. 55 and 56, allows a user to temporarily turn off the pancounter and set it to zero by pan counter button 1166. Camera tilt anglebutton 1168 allows a user to set the camera tilt angle. For a systemthat allows for either left-handed or right-handed operation, left/rightswitch 1170 is employed to change between the operations. The system maybe turned on and off via power switch 1172. Other user interfaces toprovide signals to an input device may be employed that are configuredto accept user selections, such as via buttons, switches, touch screensand the like and transmit the signals to or as an input device.

FIG. 57 depicts a further view of ECU 1162, which may be, for example,the rear panel. Connector 1174 connects ECU 1162 to motors 1118, 1128,1130. Responsiveness dial 1176 can be used to set the responsiveness ofsensors 1104, 1106, 1108, 1110, 1112, 1114, wherein sensors 1104, 1106,1108 are angular rate sensors that measure the angular rotation rate ofthe attached stabilizer plus camera about three substantially mutuallyorthogonal axes such as roll”, “tilt” and “pan” axes of rotation, andsensors 1110, 1112, 1114 are accelerometers to measure the spatialacceleration along three linear and mutually orthogonal axes, such as“up-down”, “left-right” and “fore-aft” axes. By force dial 1178 thelevel of force to motors 1128, 1130 can be set.

FIG. 59 is a schematic of a portion of camera stabilization system 1184in which the camera stabilization methods can be carried out, accordingto an illustrative embodiment. Sensors 1104, 1106, 1108, 1110, 1112,1114, 1116 output signals to ECU 1162. ECU 1162 accepts sensor outputsignals in block 1186. The accepted signals are processed in block 1188.The processed signals are mapped to adjustments in block 1190. Theadjusted signals are encoded in block 1192. In block 1192 the encodedadjustment signals are transmitted to an actuation unit 1194. Actuationunit 1194 acts on motors 1128, 1130 and pan counter 1116 of camerastabilization sled 1100.

The components of ECU 1162 can be incorporated into a single device, ormay be a plurality of devices that are functionally connected. A personof ordinary skill in the art will appreciate other or additionalcomponents that can be included in ECU 1162 to implement the variousembodiments of the methods and systems described herein, and therefore,such knowledge is deemed inherently contained in this disclosure.

In the embodiment shown in FIGS. 49-53, motors 1128, 1130 are attachedto an armature 1132 locked to gimbal yoke 1124. It is also possible, viadifferent brackets, to attach trunnion motor 1130 to pan bearing outerrace 1154 and trunnion pulley 1144 b to yoke 1124, and/or yoke axismotor 1128 to gimbal support handle 1134 and the driven pulley to thegimbal yoke.

It is noted that portions of the application refer to “camerastabilization” but the apparatuses and methods can be applied to leveland stabilize other payloads.

The invention may be embodied in a variety of ways, for example, asystem, method or device. The invention includes the methods asdescribed herein, and processors to carry out the methods, includingstorage devices and components and any associated program code.

The invention includes an actively stabilized payload support, anon-transitory computer-readable medium and a method of stabilizing apayload according to any of the embodiments depicted or describedherein, their equivalents, and apparatuses comprising any possiblecombination of elements of the aforementioned.

Various illustrative embodiments of the invention have been described,each having a different combination of elements. The invention is notlimited to the specific embodiments disclosed, and may include differentcombinations of the elements disclosed, omission of some elements, orthe replacement of elements by equivalents of such structures.

While the invention has been described by illustrative embodiments,additional advantages and modifications will occur to those skilled inthe art. Therefore, the invention in its broader aspects is not limitedto specific details shown and described herein. Modifications may bemade without departing from the spirit and scope of the invention forexample by implementing the invention for payloads other than camerasand varying positions of components. Accordingly, it is intended thatthe invention not be limited to the specific illustrative embodiments,but be interpreted within the full spirit and scope of the appendedclaims and their equivalents.

The invention claimed is:
 1. A method of stabilizing a payloadcomprising: providing a payload support apparatus having a gimbal, thegimbal having a first gimbal axis and a second gimbal axis, wherein thefirst gimbal axis is perpendicular to the second gimbal axis, thepayload support apparatus having a rotation measuring device, a firsttorque generator and a second torque generator; receiving angle θ fromthe rotation measuring device; calculating cosine θ and sine θ;receiving a selected supplemental roll torque; receiving a selectedsupplemental tilt torque; adding the product of the supplemental tilttorque and cosine θ to the product of the supplemental tilt torque andsine θ to obtain a second gimbal axis torque; subtracting the product ofthe supplemental first torque and sine θ to the product of thesupplemental first torque and cosine θ to obtain a first gimbal axistorque; causing a first torque generator to generate the first gimbalaxis torque; and causing a second torque generator to generate thesecond gimbal axis torque.
 2. An apparatus for stabilizing a payloadcomprising: a gimbal having two or more mutually perpendicularrotational axes; a motor bracket arm fixedly attached to a yoke of thegimbal; a first motor and a second motor attached to the motor bracketarm, the first motor oriented at 90 degrees to the second motor; apulley system functionally connected to the first motor, the secondmotor and the gimbal to rotationally drive the gimbal about two of thetwo or more mutually perpendicular axes; a plurality of angular ratesensors configured to sense motion about at least two of the two or moremutually perpendicular rotational axes; a plurality of accelerometersaligned along mutually perpendicular axes to measure steady stateangular orientation of the payload with respect to gravity.
 3. Theapparatus of claim 2 further comprising: a gimbal support handle; thegimbal comprising: a gimbal yoke; a pan bearing inner race; and a panbearing outer race; the gimbal yoke rotationally connected to the gimbalsupport handle about a roll axis; a gimbal yoke driven pulley configuredto rotationally drive the gimbal yoke with respect to the gimbal handle;the pan bearing inner race rotationally connected to the pan bearingouter race about a pan axis, wherein the pan axis is perpendicular tothe roll axis; the gimbal yoke rotationally connected to the pan bearingouter race about a tilt axis, wherein the tilt axis, roll axis and panaxis are mutually perpendicular; a gimbal trunnion driven pulleyconfigured to drive the pan bearing outer race with respect to thegimbal yoke; a motor bracket arm fixedly attached to the gimbal yoke; agimbal yoke axis motor and pulley attached to the motor bracket armfirst end and configured to rotate the yoke with respect to the handleby engagement to the gimbal yoke driven pulley; a gimbal trunnion axismotor and pulley attached to the motor bracket arm second end andconfigured to rotate the outer race with respect to the gimbal yoke byengagement to the gimbal trunnion driven pulley; a reference ringattached to the pan bearing inner race; a pan counter sensor attached tothe pan bearing outer race and configured to sense signals from thereference ring.
 4. The apparatus of claim 3 wherein the reference ringis locked an orientation of the payload.
 5. The apparatus of claim 3wherein the reference ring is magnetic and the pan counter sensor sensesmagnetic signals.
 6. The apparatus of claim 3 wherein the pan counter ismechanical and the reference ring is configured to allow the pan counterto register a degree of rotation of the reference ring.
 7. The apparatusof claim 3 wherein the reference ring provides optical or electrostaticsignals representing a degree of rotation of the reference ring; and thepan counter senses the respective optical or electrostatic signals. 8.The apparatus of claim 3 wherein the reference ring is locked to anorientation of the payload.
 9. The apparatus of claim 2 furthercomprising a third motor configured to act parallel to a pan axis of thegimbal and function as the pan counter.
 10. The apparatus of claim 2further comprising: an electronic control unit; and an actuation unit;the electronic control unit configured to: accept signals from theplurality of angular rate sensors and plurality of accelerometers;adjust and encode the signals; and transmit the adjusted signals to theactuation unit.